Is it okay to forge my teacher's signature?
what are you trying to achieve from that?
I was thinking about it since a long time just to prove I'm smart enough to do that.
It's not right to forge your teacher's signature for any gain just because you can. You can get in a trouble.
I'm always getting in troubles, what's the difference.
You always have a choice to do what is right if you want to stop getting into trouble. You don't have to forge a signature to show off, find another way to demonstrate your intelligence. Learn an impressive skill and show it off to your peers.