Right off the bat: yes it is entirely possible to grow taller and build muscle after 25. When I was back in high school my best friend (who went to the gym a lot) told me I should start working out with him because "I still had a few years left".
That stuck with me. Because I then spent a few years sitting around and playing video games and thought I'd missed my shot. I didn't start training properly until I was about 26/27 in fact. To top that off I am a complete ectomorph which means my body just isn't built for building fat or muscle it's meant to just stay smaller and shorter.
But I was never very good at being told I can't do something. And I don't mean that in an asshole way I just mean I can be determined and I don't like being told I have limits.
Being an ectomorph makes it harder to grow muscle but it doesn't make it impossible. Being over 25 makes it harder to get taller - but it doesn't make it impossible.
My goal was to do both. And it still continues.
I work on it harder than anyone I know. That doesn't mean I get better results than everyone. Some are naturally taller or bigger and get better results with less work. I'm not bitter about it that's just how it is. So I can either accept that or I can get up and do something about it. So I work hard. I work harder than anyone. And every day I want to push to work even harder again.
My biggest motivation in life has been someone telling me that I cannot do something. Tell me I can't get to the size I want and I will prove you wrong.
I was told back when I was about 26/27 that I was set for life. I'd never grow. My body type wouldn't allow it and I was just too old by that point. I'm bigger than they are now. And just wait to see what I do by 29.