What are my chances of getting into Vanderbilt University?

You're going to have to kick butt in your next two years and have an amazing ACT. If you don't have a 32 then you really should reconsider applying. They only accept the top applicants and your application has to really stand out. If you have Honors and AP classes offered to you then definitely take them. If not, take community college courses or see if you can take AP classes online. The kids who apply to Vandy have taken AP or IB courses with a 35 or 36 ACT.