Why do I get moist when I imagine a boy?

Don't laugh please I'm a teenager and am getting super duper curious about boys. I kissed one 4 in my cl 4 the 1st time this week & now I can't stop thinking about doing it more and touching him. It embares me but when I think about him suddenly I get slimed up in my private area-feels icky & wet. I already started my period a year ago. Why am i getting sticky is something wrong with me???? thnks.