This year, I made the decision to take the plunge and go back to school. I have a full-time job that's pretty demanding, and had been hoping that I would be able to manage both at the same time. I'll be in summer school starting in June to knock out a few prereqs before starting the application process and have been making an effort to get back into the habit of studying for at least an hour a night. So far, it has not gone well.
Good luck! I had 2 jobs and went to school full time.. highly not recommended btw. Full time job + school is doable with some preparation and some mental prep work. Especially during the beginning time frame it isn't so bad. Most of my time in school, minus nursing school, was while working.
I finish work and I'm just wiped at the end of the day. It makes me really really concerned about how realistic my plan to work while in school actually is. I love my job, and don't want to leave it, so I'm torn about whether school is actually the right choice after all. That said, I'm planning to take my career in a slightly different direction than what I've done up until now, and the trajectory I've charted will take at least 4-5 years to complete. I'm going to be 27 in June, so I feel this is probably my last real window to make a "big move" like this realistically.
School is a really flexible, and doable, thing. 27 is not your last window.. you can definitely go to school anytime.

But I think the earlier you knock it out the better! Because it really will give you an opportunity to see if that's the direction you want to go in.
My two cent advice based on my experience:
- Balance out the semester. See what your end game is: Associate's degree? Bachelor's? Masters? Whatever it is, look at Every class you will take the entire 1-4 years and balance them out so that you have a good mix of 'hard' classes and 'easy' classes. It will get progressively harder as school goes on, but if you can break it up a bit with some gym classes, speech classes, and other requisites that are less demanding it smooths the semesters out a lot more.
- Gauge it with the summer and 1 early semester. See if full time is an option for you. If you're too tired, drop down to part time. Yeah, it drags everything out, but seriously don't sacrifice your health and sanity. You should enjoy both.. overloading yourself will make you hate all of it--your work and school. Maybe you can balance it and be full time one semester, part time one semester, or part time + minimesters and summer semesters to make up for it (I don't know how your college works, but mine had mini semesters in the winter holidays and such). It really IS that flexible. Use those beginnings to figure out what you can handle.. because really, maybe you find out as wiped out as you are from work, it isn't that bad. If it's just the homework and not the course work itself, you'll probably be fine.
- Consider community college for as long as humanly possible. I don't know what your background is, or where you plan to get high educations from, but community college is amazing and its existence alone saved my college career. It is far less pressure, less cost, and more help and opportunities for scholarships to cover the costs. I went to see how many max credits can be used to transfer, found out it was 69 (haha), and went to CC for that many credits exactly. I also researched which colleges I'd potentially go to in my area and what classes they would or would not take from the CC.. sometimes colleges require you take THEIR speech classes, or their writing classes, and they will only accept x type of course work. Nothing sucks more than having to repeat a class you already paid for because of red tape bullshit.
- Consider online classes for some easy courses. If you read some reviews on ratemyprofessor and an 'easy' class and it seems like they're a great distance professor, online classes can really save your ass. I would go to the library and do it, but it was great to be able to do my whole class on a friday night instead of NEEDING to go on tuesday/wednesday. If you don't like online classes, there are many times hybrid classes as well--some online, some in person, to give you some time to yourself.
- Make sure ONE day a week is to yourself each week. Don't put school on your off days.. As wiped out as you think you are, don't book both of your off days. You need that to catch up on yourself and have a life. What I did: I booked my classes during work day nights (as tired as I was, it was better to just be tired and go to class and take notes/record the class), had one day off to clean, catch up on homework, etc. and one day a week to myself. I studied between classes, on lunch breaks, before work, after work, whenever. The slots in my day I had 20-30 minutes, I'd get shit done then, because that one day to myself was miiiiiinnneee.
- Take this time now to research your eligibility for FAFSA, grants, and scholarships, and apply to as many as you can. CC's are usually pretty helpful in this department.. mine definitely was at Lone Star CC. Having extra money in your pocket to help out with school makes it a LOT more doable.
- Blitz through your homework. Do it on lunch breaks, and write papers and bigger projects on your homework day. I spent 8-9 (took 12-14 hours total) hours on homework each week all in one day a week out of 2 I had off, and it was time well spent. I wasn't at work, I wasn't using it for myself (yet), but I knew the next day I could just sit back, relax, and Ahhh...
- Don't neglect your health in the process. Look up some easy slow cooker meals or something, or set up an easy thing like instant oatmeal, sandwiches, and spaghetti for dinner.. whatever you gotta do, keep it going.
- A water bottle and lots of hydration can keep you awake. /armytricks.
- Keep food in your car if you don't already. >.> Wasabi peas and spicy snacks I frequently found were needed to keep me awake and alert in class, so I could just run to my car on a 10 minute break and grab some.. and sometimes a couple breakfast bars were the difference between me blowing $12 at the cafeteria and saving that moolah.
- Make sure you take classes you like too.

have something to look forward to.
- Participate in class. Nothing keeps you awake more than being active in class, trying to answer questions, and asking questions.
Anyways. Those are my suggestions. really, the major thing is, find a good balance. If you can only take 2 classes at a time, that's more than you had before. If you can handle 4 at the beginning, but need to drop to 2 when it gets more science heavy or major-related heavy, do it. You'll be fine.

Plenty of people power through school, I know you can do it too--and not dread it.