Sneaky link?

So I’ve been messing with this guy for the past like 3-4 months and we’ve had sum fun but we actually haven’t done anything in person at all, I see him at school and he sees me but like I try to keep it as lowkey as I can and then few weeks ago he asked me if i wanted to link I said yes but I’m kinda nervous because if we “link” it’s gon be my 1st time and idk if u should tell him or what I’m a lil confused on this and recently I’ve been having deja vu that I end up pregnant and shit ( keep in mind we both 18) but I just don’t know what to do exactly or how do I prepare myself for this sneaky link. If we do link I want him to want more and not just a 1 night stand but idk what to exactly do! Help?!!