Oh! Ohh! Sorry!
Don’t be. I was so nervous myself, for real. If you’re particularly small or tight, lubricant helps out a lot. Also, ask your partner to go nice and slow with you and to rub your clit while they penetrate you. Warming up with fingers is also a great route to go.
Also, penises are just kind of creepy and horrifying to look at sometimes. Honestly. No shame there.