Scarleteen

I’m nearly 19 and I’m still a virgin Me and my boyfriend are planning on doing it soon.it will be protected. Will this affect my period doing it the first? And when will it go back to normal if we do it every so often?

Hi Anonymous98

Welcome

Having intercourse shouldn't affect your period, as long as you are using some form of birth control e.g. condoms, although some kinds of hormonal birth control can impact on it.

If you're planning on having intercourse, why not read this article and explore some of the links in it?
First Intercourse 101
Is there anything more you'd like to ask or want more advice or info on?

When is the best time to do it during the month?

There's really no best time to have intercourse. I assume you're asking because you're wondering when your most fertile times are (correct me if I'm wrong!), but that's something you can only calculate through charting pretty intensely for several months, as we discuss here: Fertility Awareness (FAM)
If you're using at least one reliable form of birth control, though, it doesn't really matter when in your cycle you have intercourse, since your birth control method is working to prevent pregnancy. Do you want any information on what your birth control options are?