I'm now 20 years old... Am I supposed to feel any different?..

Nope, but wait till you hit 50 and realize more than half your life is over.

Give it another 8 years before gravity starts sinking in

Nope, enjoy the monotony

Lol you'll feel it in a few years

Congratulations old lady.

No, it's just another number. Change happens gradually ... or rapidly but unexpectedly, not to a timetable :(

Only birthday I felt different on was my 15th.

I didn't feeel any different either

Nah :)