Just wanted to give my 2cents. I also rushed late (I'm in my 2nd quarter as an initiate and about to be 22). I go to the University of Cincinnati, but am originally from NE ohio, where are you from?
Anyways, drinking is not an issue, and neither is hazing. Hazing does not exist, and if it does, that group is not good enough for your membership. Drinking is not mandatory, and not necessary. In fact some of our most positive and influential members drinking little or nothing. It allows them to represent themselves to the best of their abilities without alcohol interfering with their judgement.
And joining late has its perks and faults. First the perks. Though I have heard rumors of sororities not offerning bids to older girls, I didn't have any problems. I joined several student organizations in the last year, and they all sited my age for the reason I was offered membership to these orgs. Typically the older a student gets, the less involved they become. These groups were all impressed that I had taken the stance that I had taken from my university and community for three years, and that it was time I started to give something back for future generations.
Additionally, being older allows you a little more perspective on the situations you will encounter, and allows you the ability to not react to strongly to stuff that seems big to freshman, but then can be seen to be minor as you get older. Age brings wisdom and maturity, and both of these traits can be used to benefit your chapter and your life. Each of our chapters have achieved greatness through the hard work of our predecessors, hopefully you will be able to continue that tradition in any chapter. (As a side note, I gotta hype my campus and chapter!!!).
The one strong downside to joining a little later in life is that is a bit difficult to fit in at first. Your pledge sisters will be 18-19, and the bulk of your chapter will be <21. I didn't go to fraternity or house parties anymore (yeah bars!), and I didn't live in the dorms. So bonding took a little more work, and a little more time. But overall it was a great experience. I knew my experience would different from my pledge sisters when I walked in the door, and so everytime I got discouraged, I just remembered that everyone around me was a wonderful person. Some of us were just at different places in our lives.
Hope all works out great for you. If you decide to go XO (we have a chapter at BG), then let me know. Otherwise, I wish you tons and tons of luck.
XOcrlstln