Condoms..?

The first time me and my boyfriend ever had sex, my period was a week late, and normally my period is right on time.. did us having sex cause my period to be late for the first time ever since I've had it?
Another question, how well to condoms protect you from getting pregnant? Me and my boyfriend only ever have sex with a condom, but I'm not on
birthcontrol. How high are my chances of pregnancy?
thanks in advance.

Yes, having sex, is something new to your body and your body needs time to adjust... so it'll screw it up. Just like how teenage girls miss it when they're stressed or over working themselves. Condoms are only 97%. You can still get pregnaut just using that... be safe and go on the pill too!