I'm 20 going to 21 now.
it's not the age to watch anime anymore, but that is what i thought.
But some animes are just too good for children or teenagers to understand, such as the subtle jokes, the references to Japanese culture, lifestyle and the language itself (most probably one of my reasons of taking the language itself), and to appreciate the intention of the author; and too unrealistic, dreamy, impossible and ideal for adult especially the seniors to relate it to real life that they have experienced.

This is just the right age for those anime. They are just like artworks: a message to deliver, a joke to tell and a story to share.
Some animes are just a time killer, you watch them when you've got nothing to do or when you just don't want to do what you are supposed to do. There times that some people becomes a fanatic due to being over-passionate about anime but it's nothing wrong, because some interesting ones are really masterpieces or great minds.

Doraemon is what? just a nonsense about a robot traveling to change a future of a hopeless guy with all its ultra high-tech tools? It has lasted over 50 years inspiring youngsters through a fun way. It was fun when you were young watching it on every Sunday morning, but when you re-watch it again at this age, you know that these two are the great minds with their masterpiece crafted over years of experience of drawing other predecessor manga and trying to tell people what they want to tell through the light and fun ink on their drafts. You know Leo for his Monalisa, and if you happen to know Fujio Fujio, it would be for their Doraemon.

Well, right now I'm clung onto this interesting
one: Gintama. I won't recommend you to watch, but I'm really glad to have been able to watch this anime with vague storyline but great gags, lame jokes and jokes, and sometimes amazing inspiring values that the author believes that everyone should believe in.
just read some of this titles:

"Make Friends Who You Can Call By Nicknames Even When You're Old Men"

"In troubled times, go and laugh, go and laugh"

"The things that don't matter are the things you can't forget."  

"There is data that can't be erased."

"A woman's best make up is her smile."  

"The taste of overseas Japanese restaurants is generally at the same level as a school cafeteria" (wow really?)

"Even if your back is bent, go straight"

and many more. Well, not all episodes are as interesting but when an episode is intended to take your breath and amaze or inspire you, it will never fail. Same goes to how it can burst you to laughter.
And this is just the right age to watch gintama, not as young as when I just sketch because my mom asked me to, not as old as when I've decided on my priorities in life and just devote my life in that.