yikes.
ok, from an older girls stand point.
first, there was one huge err in the op's plan for intamacy.
anytime you are going into a situation where intamacy, and sexual activity is possable, you must carry lube.
in all the years, with all the girls ive talked wih, lube is essential. it aint gonna be pleasureable without it.
check at your local pharmacy, they sell single use packets of lube that easily carry in purse or pocket. stash a few in the car, the purse, etc.
a great time to apply is when he is putting on his condom. PLEASE, dont go there if hes not weraring one. we are just as likely to contact STD's as any other girl. also it greatly increases the chances of a bacterial infection, and makes clean up much harder if hes not sporting a rain coat.
Early on in my post life, lube in place, an extra setting near by, i would have previously made sure he knew about me, and at that moment, I would remind him . some of my lines were, ' be gentle, take your time, its not broken in yet" , OR, " its scared, so go easy until it gets to know you".
i learned also, that though a guy isnt like plastic, and the penis will fit even if a bit bigger then the dialiator, there is a point where i say no way. a guys size can hurt, even if it fits. im not the type to just ' do it' to make him happy, while I lay there in pain or extreme discomfort. ill let him bitch and moan, call names, what ever, its my cooter, its my call. ... its not like you can measure it before things get hot. and when that critical moment arrives, and he flops out something that resembles a Anaconda, thats as thick as your wrist, you have to make the call thats right for you.
never be afraid to say "NO"
a lot of us older girls also only got 6 inches of depth, on a good day. so all the above applies to a guys length. we all trust them to respect our limits, but we also know how that can go. some will find that the thicker a dialiator is, the less depth they realise. that applies in the real life experiance also. in time, you learn to guage what will work, be comfortable, and safe.
bottom line. you are only so big, so deep. Part of the sexual equation is that it be pleasurable and enjoyable for you too. lube is essential so carry it all the time, and understand that some guys may just be too big for you. there is no shame in that, or in saying no at the last minute. Even genetic females will tell you that. only you can protect yourself in that way, and as for condoms, no rain coat, no play. that should be a firm rule every time.