How can I not be afraid of having ?

Lol such sketchy question, but I grew up in a religious environment and I truly feel that is bad! That if I have it (even with a boyfriend of a year or something) I'll be a bad person or tainted for life. :( I'm almost 20 and I plan on getting married in like 10 years, so the waiting for marriage thing would be torturous and I'd probably regret it. Can anyone help me think of in a different light? Like, why is good (lol can't wait for some of these answers) and not just something that is immoral or something that will lead to heartbreak? And thank you much for all of your answers!