It would be strange if a 16-year-old dated an 11-year-old. Yes, you and she are both adults, but she is still evolving. She'll definitely change a lot in the following few years. I'm sure I did. I'm not suggesting you shouldn't date her, but I would keep things light for a bit. Maybe go out for dinner once a week or so.
Here's why: People change as they grow up. Your girlfriend will no longer be a child at age 16; she will be a young woman. A young woman who can make her own decisions about where she wants to take her relationship with you.
If you aren't ready to think about marriage and children, then don't worry about it too much now. Wait until you are ready. She's going to need time to find out what kind of person she wants to marry anyway. In the meantime, have some fun together and don't feel like you have to rush into anything.
A tween exists in both childhood and adolescence. An 11-year-old girl is no longer a child, nor is she an adolescent. She's in the midst of the tween stage, which refers to children aged 10 to 12.
Here's what to anticipate from an 11-year-old, from intricate social dynamics at school to physical changes that might confound and humiliate a tween. Physical changes are common at the age of 11. Puberty may have already begun for females; for boys, it usually begins later (around age 12), but it is not unheard of for boys to begin before the age of 11. Definition Writing Tips
Make direct eye contact and smile. Without saying anything, make eye contact with a female to let her know you like her. Look her in the eyes, don't shy away, and don't look below the neck at this moment. If she looks you in the eyes, smiles back, or blushes, you could have a chance. If she frowns or says, "What the heck?"