Just need some advice!

So I’m making this anonymous because I’m really scared of being judged and hated on so yeah 😅 well I’m only 17 (about to be 18) me and my boyfriend had unprotected sex 3 weeks ago well it’ll be 3 weeks on Thursday and my period is 5 days late. I want to take a test because I really wanna know because I’m very excited (no we weren’t trying on purpose but we’re still happy) I know 3 weeks is still a little early so I’m trying to decide if I should take a test or not. I’ve been having headaches frequently and my CM has increased. I have no idea who to talk to about it because my parents are super strict. Should I take a test on Thursday when it’s exactly 3 weeks?? I’m still young so I don’t know a lot about what I should do but I’m very anxious and really want to know and so does my boyfriend...please help!!