How do i know if i'm ready for sex?

okay, so my boyfriend and i have been together for over six months now, and we get out of school for summer break in a week. both of his parents work, but both sometimes come home(rarely). and i don’t live with my family, but my guardian’s job is running a daycare at our house. she sometimes goes on all day field trips to the zoo and what not, so there have been times where i have been able to sneak him over( we’re not allowed at each other’s homes when no parents are home). we have done everything but have sex. he’s gone down on me, i’ve done down on him, even sixty-nine. but i’m still really nervous at the thought of sex. i just don’t want to risk getting pregnant, or getting caught. we both really really want to, and sometimes i think i’m ready, but i’m not sure. opinions?