I really *ditto* darkeyes" post. I'm happy for you that you have this really awesome relationship with your b/f. If what you feel for each other is going to turn into a life long commitment I think you and your b/f need to discuss several things.
You said that you both have severe mood disorders but that you help each other out. That's great, but what if you both experience these problems at the same time? Do you have a back-up plan? My husband and I both suffer from depression. When we first were married we used to joke about how both of us couldn't be "down" at the same time. Well the joke turned into a reality that had a very negative impact on our relationship.
Are either of you under a doctor's care or involved in therapy? It might be something to discuss with your b/f.
I have a son who is almost 18......he has what he calls the "most awesome girlfriend in the world". They are having a great time. He took her to the Winter Ball at their school last weekend. AAHH....young love : ) But...LOL..there are also times when he gets home from school and says "women!!!!!! I don't understand them at all!!!!". Now the two of them may one day marry, but they have both agreed that they each want to finish college and see if they still feel the same about each other.
You mentioned that your b/f wanted to be married by the time you were 20. Is there a reason why he picked that age? Could you suggest to him that you would prefer to say like somewhere in the early to mid 20's? How would he feel about that?
I think that you've shown a good amount of maturity by posting and asking for advice/suggestions

And I always love seeing young people in love.....but there are many responsibilities that accompany marriage. Enjoy the relationship that you now have, but please think about the suggestions offered in all of the posts you receive.
Please feel free to let us know how it goes, ok?
Sweet
"It's never too late to be what you might have been". George Eliot