Personal opinion...... I believe you will be just fine, but......
doing Kegals will help make the muscles of your vagina stronger....(that is pee, stop, pee, stop, pee, stop several times each day)...giving you more control.
Others can comment about vinegar which may remove the healthy bacteria in your vagina....probably not a good idea if used often.
You guys can also have sex missionary style, (you on the bottom).
He can use his arms to raise himself up so that his penis, hands and knees touch only..... allowing more blood flow to the penis..you will feel the difference.
His penis will actually grow bigger during intercourse and at ejaculation and hopefully fit real tight..you might have to stimulate his penis manually to get things going first. Another thought is use Eros silicone lube for a tight seal. Try it and get back here.
But again, I'm guessing you should be just fine.