That's great Giggly. MTB is fun, challenging and awesome The best thing is there are trails for every level of experience. I have a road bike too. I cycle 35-40 miles when I have the time but mainly now it's down to 15 miles.
I like pushing myself. Pushing past pain or beating your best time. I like the fact that cycling allows you to compete against yourself and when you do that you strengthen yourself mentally. Basically, that physical toughness can translate to other aspects of your life. You can channel it.