Our age doesn’t have to restrain our emotional diapason. There are no actual rules of how we have to behave ourselves. But our social and natural environment usually limits our behavior. It’s also true that older people improve their emotional well-being from early adulthood. They better understand the importance of positive reflection on life. 
And all the small moments of excitement and happiness capture our life better than you think. Isn’t it great that we can amaze ourselves at any age?