If you get fingered through your pants after a boy touches his penis can you get pregnant?

No: If you have a barrier such as clothing no sperm will be deposited in the vagina. However, at 19, the heat of the moment is bound to catch up with you at some point. I suggest you think seriously about contraception options if you are not ready to support and care for a baby/child. While a miracle, they are also expensive and time consuming and you need to be fully committed to being a great parent