I'm sorry, 'Absolutely not' wasn't an adequate answer to your question pink kitty. Firstly, a penis, however long does NOT penetrate your cervical opening. Imagine your vagina as a tube with a closed end. The cervix protrudes into that tube from one side (usually from the front). It isn't at the very end. So the penis head goes past the cervix and presses against the closed end of the vagina.
Try feeling for your cervix with your finger. Keep your palm and wrist towards your clit and feel your way in with a couple of fingers. About 3 inches in you'll feel a bump like a big nipple, that's your cervix. You'll actually go past your 'G' spot on the way to your cervix. Let me know when you find it.
A guy with a small cock can reach your 'G' spot and cervix (unless he's very small, ie. sub3"). As I say, an average cock (approx 5"-6") or a larger cock will go past your cervix. You might be able to feel the coronal ridge glans knock your cervix on the 'out' strokes.
There are many web sites which give information about risks regarding cervical cancer. I'm sure you'll find that the size of your partner's cock is no cancer risk for you.
Riven650