Go to a Music Festival
You should go to a music festival before you turn 25 just to experience the vibes and the feelings this people have there. Enjoy the music and perhaps a drink or two. And of course don’t be shy and dance.
Travel to another country
You should have travelled to another country. Experience new and exciting things. Learn about other cultures and try to understand them. Everyone lives differently.
Have learned a new sport
Yes, you should have learned a new sport before turning 25. Doesn’t matter what, football, ballet, ice hockey, whatever just something that gives you the feeling of achievement. If you learn something new, your brain will have the feeling of achievement.
Make an investment
I know how that sounds like, “I’m 25 how am I supposed to make an investment without money”. Yes I know, but til 25 you’ll have a little bit of money saved (hopefully) and I think you should invest it in something you think it’s going to be worth it, maybe also for the future.