Age... is it a number or a state of mind?

Someone once said on their 40th birthday that they were glad to be turning 40 and that the 30's were the hardest years of their lives. Imagine my suprise, at the time I wasnt even close to 30. I pondered this thought because I've always looked forward to being another year older. For me ,you see, it was a number in hopes to finally match what I felt inside. From a young age, I was told I had an 'old soul', I never " fit in" with those my age. Aside from my few high school friends, everyone was older. Each year that passed, I failed to realize that those older friends too would be embracing age also. Their children finishing high school, as mine were awaiting to be born. Now their children are moving away and mine should be starting school. They are celebrating 20+ year marriages to my upcoming 10. Is age a number, a mindset, or a life event? I wish I knew, I just pray one day everyone can be accepted for who they are and not what their age or their life situation.