I think you need to calm down about the "This is my only chance" thing. Someone is going to marry you, be in peace with yourself about that, marriage is a lot more than just atractiveness and trivial stuff, thats just the beginning. Marriage is a bound where man and woman build a life with meaning together, is something that if you take real serious, you will get a lot of benefits from it in you life.
The other thing is that I know from experience that sexual desires are very strong and difficult to avoid, but believe me, 90% of the girls I've met (as friend or as a couple) would change their "first time" if they could go back in time.
Sex is something so powerful that it can really destroy your life, believe me, you are not mature enough to dimention it and even we live in a culture where sex is such a natural and normalised topic that you may think it's normal for you to have intimate relationships.
Believe me, that would be one of the biggest mistakes of your life, me as a man, if I could go back in time, I would've wait until marriage because when you have your first time, sex will always have a space in your life, and that isn't something you want in your early life.
Just trust us and don't believe that we are "stupid conservatives" or something like that, many of us ruined a part of our life because of sexual sin, It isn't something to just earn heaven in a Christian context, is something to be at peace while you live in this world.
God created the sexual mechanism so strong for a reason, for a succesful reproduction and an intimate and unique conection with your husband.
I used to be an atheist for 10 years or so, and I know I'm not late to understand this, sex can really wreck your life, you better be a little conservative about it at least.