might be pregnant and thers a 4 year age gap

i’ve bin with my bf for 2 weeks and 4 days am 15 and he’s 19 i told my mum he’s 16 and he told his mam im 17 we love each other loadz and we don’t wanna b seperated. i might b pregnant and it was scott who mentiond it first cuz we hadn’t used a condom a few times and he said if you are pregnant we need 2 think about a abortion and i said no i don’t want 1 n e sed why so i just said cuz i don’t so he sed ok and now he’s well happy at the fort of me bein pregnant i was due on (ma period) on the 18th may and its the 21st today he wants me to take the test this thursday so he can find out if am pregnant or not but i want to take it sunday so we’v gota work out when am takin it but the main problem is telling are parents and were going to have to tell each others parents how old we really are my mum and dad like scott and i get on with scotts mum and the 2 brothes iv met but am just abit worried it might corse conflict between are parents and us his 2 bro’s no hw old i am and they ain bovard its just the parents i need sum advice i don’t no what to do