Well, u sound like my dad lol. But I would help u out abit. With hearing, best way for get sign language to communicate. Hearing had to understand deaf cultures, cuz sometime hearing feel left out. But Deaf feel same way with hearing culture and left out. So that way ur daughter can have socialize in her life and communcations easy flow in the relationships.
Other thing, have to let her go too, since she is grown up girl now. She will see in her own world, and she made her own decision, i'm sure she aware and whats best for her. I know its hard, but ur little girl is grown up.
My parents been tears for me all the time when i was turned 17 yr old, which gone to pre college. My dad always wrapped me as protective when young guys stand around. He dislike to hear those guys statements about me. Such like whoa, she is sexy. Believe me, it make me awkfard around with my dad. But he started understood i'm grown up.
Please take easy on her, and support her whenever she ask to. Just don't jump conslustion and try to listen. Maybe she will come to you for advcie or talk to. Have a great father!!!!