Sex and pregnancy

I’m a virgin and I wanna have sex with my boyfriend were comfortable w each other and I think we’re ready for that step but I am beyond scared of getting pregnant and I can’t go on birth control cause I don’t want my mom to find out I guess I wanna know if condoms are actually reliable and I’m pretty sure they are since everyone else uses them but i also wanna know if anyone else had this worry before/ during their first time