I actually had a similar experience when I started college. After coming from a 'meat-n-potatoes, clean your plate' household to an environment where I could have fresh fruit and veggies whenever I wanted, I also lost about 50 pounds in my first few two years of school.
It's great to see that you wrote of your excitement to join the lifelong journey to health! After maintaining for five years, it was only because I forgot about that 'lifelong' part that I got out of shape and found myself back here.
Congrats on all your hard work so far and welcome to the site!