You haven't done anything wrong! Reasearching what you're getting into and learning how to have your best rush is certainly advisable. Do check out many of the recruitment threads here--many have been stickied. Along the way you'll probably figure out why some bristle at these threads, mainly because some girls come here for advise on how to get THE sorority they want. Period. Then they just stop listening.
You certainly won't be the only girl from OOS so unless you use the same moniker elsewhere or it's got identifying info in it you should be fine.
UT lists some Panhellenic alumnae associations that can help. (Below--there are probably more in your area) Register with one close to you for info on rec forms, etc. Some have conversation workshops, meet-and-greets, and the like.
UT rush can be different animal, of sorts, so do some homework. Taking everything online with a grain a salt can still be helpful and you can get a glimpse of what some of it will be like. What dorm you may be more comfortable in, etc. Reading old articles and even *gasp* threads on other sites can still help you get a glimpse behind the curtain.
There are many great sororities that take OOS girls but you need to be prepared that the process can be bewildering and painful. But also fun! You just HAVE to be open to giving the groups that want YOU an honest chance. If a house cuts you because you didn't summer with any of them, you probably would be happier elsewhere. Truly. And Instagram can be very dishonest--remember that.
Good luck to you, and congratulations on becoming a Longhorn!!!
http://http://deanofstudents.utexas....pc_alumnae.php