I think I might be pregnant not really sure lol

Well I’m 16 but recently I been having and a downloaded an app just incase since it’s too early to test but today it says I’m 3 weeks and exactly today I’ve been having very sore boobs I've had like a bit if a tight feeling in my lower belly and it hurts when i bend down or suck in my stomach so i was wondering if any mothers experienced this or are going through something similar