Congrats, that is very exciting!
I've gone down about 2 sizes over the past 2 years. I gave away my bigger sizes slowly. I had a lot of trouble giving the clothes away at first because I had to work so hard to find some of those clothes (larger sizes aren't always stylish, plus i had to work hard to find taller/plus sizes too). I was so scared that if I gained weight again, I'd have to start all over. I knew that I shouldn't hang on to them as a safety net, but I did. Then I just started pulling a few things out of the closet every few days or weeks, and I would try them on and think, This is ridiculously big on me now! That made it easier to donate them, give to friends, etc. I actually just filled up a bag the other day, and I think that will be the last of it for me. I will no longer have any larger sizes in the closet. If i gain again, well, I will either have to go spend all that money and time buying a size I don't want, or it will give me a kick in the pants to lose a few pounds to be comfortable again. Good luck with your continued success!