Gf giving our baby her last name

My girlfriend and I are expecting. It was unplanned. But we are in love. Both in our mid 30s abs will be each of ours first child. She is giving the baby her last name. I don’t like this. She says it will have whatever her last name is. I do wanna marry her eventually but how do I know she will say yes. Than the child will never have my name. I will always be in the child’s life so I feel our child should have my name. She could eventually marry someone else, and then what.? She might give it that dudes name who knows. I feel like this is a snap in my face and disrespectful. Anybody been in this situation and how did it all work out? Any advice is helpful. Thanks. Oh and hyphenating is not an option. We both don’t want that.

Did you even ask what her reason was? And has there been any serious talk about marriage? Maybe it's time to get on that a little more aggressively.