I can look at it from two different angles.
When I was 21 I was with a guy a lot older than me for a good few years. He was very young minded and was far more laid back than I was. My folks were ok with it as he seemed younger and calmed me down a lot. If they hadn't have been ok with it, they would have just had to deal with it as it was my life etc.
Now, on the other hand if my son brought home someone who was a lot older than him when he was 18.....I'm not too sure how I would deal with that.
Tldr.....I think its ok until it directly affects me then I might feel differently
