Hey, now is a great time for you to learn what the Catholic Church teaches about sex. (For reference, I'm 25F, teach RCIA, married 9 months ago as a virgin to a virgin and... We have a great sex life.) Here is it in a nutshell (but there's so much more to say): what is sex designed to be? Sex should be two people uniting together - giving themselves to each other as a total gift - that is free from coercion and open to the possibility of creating new life (having kids). As Catholics, then, we understand that sex only belongs in marriage because two people cannot just unite their bodies and say, "We're united!" They also need to unite their hearts, minds and souls (hence the marital vows.) Catholic marriage also isn't based on a feeling of love or commitment or excitement or whatever. It's based on the idea of vocation: two people are called by God to be in this relationship for the good of the other (not them!) and have made vows before God and Church that confirm this reality.
So what is sex outside of marriage? Whether people know it or not, essentially it's a selfish lie. It's saying, "hey I really like you/your body/your companionship and I want to enjoy you in the most private, intimate way that two bodies can... without having to commit to you with my whole heart. I will not be patient and grow in our relationship in other ways - I just want to feel pleasure given to me by you (but it's okay because I really like you and you like me and you're okay with it.)
Now, that's probably not your intent. You're probably not out to use this girl. It sounds like you're really inspired by her - which is beautiful! But by having sex, you two would be using each other. Matthew Kelly, founder of the Dynamic Catholic Institute, wrote in his book "The Seven Levels of Intimacy" that the highest level of commitment should match the highest level of (physical) intimacy. There are so many more and better ways to access each other intimately than jumping into bed and it will be MORE FULFILLING because sex was not designed to be enjoyed outside of marriage. In other words, there are negative consequences.
Check out the chastity project ... Check out that book I mentioned ... Check out the Catechism of the Catholic Church and read their section on the Sacrament of Marriage. Do your research before making a decision. And remember that every single person gets tempted - but that we all must throw ourselves on the mercy of Christ in order not to fall into sin. Lent is a time to remember Jesus' 40 day fast which culminated in those big 3 temptations from Satan. Jesus wasn't even exempt from temptation.
Make the smartest decision you can and use the Lord as your guide. Pax Christi, my friend.