Wow, what was the context of being called "simple" and "boring"? I am trying to consider a scenario where I would not be immediately very insulted and end the conversation. It's a big difference if someone calls your outfit "boring" or tells you that you have "simple needs" to telling someone they are "boring" (period) and "simple" (period).
I think more important than the relationship with the INTJ here is the principle - don't let anyone make you feel like crap. You do NOT have to put up with it. And often the simplest thing - just speaking up and saying it out loud - makes a world of difference. This is an extremely important life lesson to learn now. There will be many more people like the INTJ in your life.
If the relationship ends, it ends, but you owe it yourself and even to her to explain yourself. At least give her a chance.
But for sure, tell her how insulting her comments are to you and more importantly, how you feel she looks down upon you and why. Tell her you don't need her to agree with your life choices but you need to be treated with respect. You can also put a little bite into it and say how ironic you think it is that an INTJ (her) would call someone else boring. Explain to her that there are many faults of hers that you could point out, unsolicitied, but you don't because of X, Y, Z reasons and that is why you take offense when she does it to you, in the way that she does.
I think from that point once you tell her how you feel it will all be about how good you both are at communicating. If she's willing and able, she might tell you that she does respect you and she is just talking to you like she talks to "everyone else". A good response here is that you are *not* "everyone else" and that you've invested enough in each other to be worth a little more effort. Etc.
Honestly, I've seen similar confrontations/conversations go either way, to an extreme. So much is out of your hands and so much relies on both of your comfort levels with confrontation. So I wouldn't worry too much past the part where you say your piece. The goal here is to get it all off your chest (in a constructive way) and put the ball in her court. That should be your focus.
At the very least, it will be a good exercise and opportunity for you.
Tell us how it goes!