Hey! I'm 21, I'm at 175 and I'd LOVE to help ya out!
I'm starting Jillian Michael's 30 day Shred today, i got it for $10 at WalMart, there is a thread for it here in the 20-somethings section. Maybe you've already tried it, but I've heard it can really help with those plateaus!
I'm starting a blog to track my progress on it, as soon as I've done my first workout I'll post an entry and I'll message the link to you if you'd like!
Good luck! Keep drinking tons of water and just don't give up- you've come a long way!