Am I (30F) overreacting over my bf attitude because his age? (28M)

My bf (28M) and I (30F) have been together 7 months, but we have known each other since last year. I had never dated anyone younger than me so this is practically new to me, at first I thought that the little age gap wouldn't be a problem because, actually, he is very calm and really is able to listen and to change when we have discussions. And so far he's been really good until recently.

It has been very common that he comes home late on the weekends, he's hanging out with his friends (I actually met some of them, it's a big group and they're both female and male around like 23-28 years old. I don't like them because I think the way they act is very rude to others, they gossip about each other and even one guy in the group committed SA to one of the girls and no one did absolutely anything!!!! And I know my bf isn't like that so it's very hard for me to understand how he can be friends with people like that)

They hang out like two or three times every month maybe, so they go out all night, go to bars and sometimes drink at one of the guys places until like 6am. It's not always, but sometimes he disappears and doesn't give me any updates (I don't mind if he's with them, but I worry about him because sometimes he has to drive from the city to the province where he lives and he doesn't sleep until he's at his house. One day he had an accident on the road, cause he didn't sleep at all, thank God it wasn't that bad and he got only a few bruises but I was really worried about it. So we made a deal that every time he goes out he has to tell me that he made it home, safe and sound) But this has been more and more repetitive over the last month and I don't know if it's because I'm slightly older but I don't want someone to come home every weekend until the morning and drink all night. I think that was cool and fun when I was in my early 20's but now I find it very difficult to keep up with that life style.

I haven't talked about this with him because I don't want to sound like I'm his mom or something, but I don't feel comfortable with this situation. How can I talk about it without sounding like I'm giving him a lecture. He's big enough to make his own decisions and know that everything has consequences