Boyfriend said im “too old” to post on social media

So I’m 26 years old, my bf is 27. He doesn’t have social media but I do and I rarely post on it, I post on it like once a year. He looked through my phone the other day when I left it open and went to the bathroom and he went through my Instagram. Also he knows I have social media and says he doesn’t care but he saw a picture I posted in a crochet top that I made that I thought was really cute. It wasn’t overly provocative or anything. He got really mad and started a fight about it and said I was too old to be posting stuff like that. Which I think is weird because I’m not allowed to look cute? I’m just supposed to be homely now or something because I’m in my mid 20s? And there are people that are older than me that post stuff like that too so I just don’t get it. It made me feel really bad like he thinks I’m old. Am I really too old to post on social media and look cute?