Abortion/Pregnancy Questions

I made a bad decision and had sex on day one of my fertile window without protection... He pulled out, but I know the chance of pregnancy is still there. I am 17 years old and will be starting my last year of high school this month. I have plans of going to college. My parents hate my boyfriend and would be absolutely crushed if they found out I was pregnant - they still think I'm a virgin. He is the only guy I have ever been with and while I love children and babies, I am not financially ready to have one at this age. The last thing I want is to disappoint my family. I turn 18 in 3 months. If I am pregnant, is an abortion at 3 months too late? I want to wait until I'm 18 so I don't need a parental signature. Do you have to pay upfront, and how much does it typically cost? Have you ever had an abortion, and if so what was the experience like? I know that I sound incredibly irresponsible... I feel horrible about the decision I made to have unprotected sex and while I know I will feel horrible about aborting if I am pregnant, I know it is my only option. Thank you for any advice you may have.