Dear Monica, 

The sister you spoke to taught you the most beautiful and necessary prayer there is. 

You have several things to take care of. In all probability if you join a community you will have to have your student loans paid off first, but that is something you will have to find out from the groups you get interested in. Keep in mind that a particular community might also have a preference as regards what you study in college. For these two reasons it seems to me that while you pray your prayer until your heart changes, you should begin to look actively into different religious orders. Start with those you already know and may be already interested in. Speak with their people. They will be able to advise you as regards your studies, let you know their policies as regards loans and debts, get to know you and see if the signs of the call are there, etc. 

I would highly recommend that you do your projections and see how much your debt is going to be when you finish college, what opportunities you have to lower it (work, etc), and perhaps reorganize your life to start chipping away at it, especially if you find out that you need to have it paid off to join the place you are most attracted to. So, you have to tackle both ends of the problem at the same time. 

It might seem I am presuming you have a vocation and pushing you to take steps toward it, when all you said was that you are thinking of it, you're not really sure, and you are attracted to marriage as well. Well, when a normal person begins to think of a vocation to a degree where she asks advice about it and thinks it might be a possibility, I think it needs to be taken with respect because the Holy Spirit may well be at work. So, even though you are not sure, and are attracted at the same time to marriage, the best thing to do is give God a greater chance to speak. You do this by praying and by looking into the vocation (visiting religious communities). If you do these two things, it will gradually become clearer what you should do. 

God bless.