I have been an extroverted kid, then became big time shy and timid as a teen and now getting out of it.

From experience and observation, I would say, you being shy and timid so far doesn't mean you have to be like that forever or you will be like that forever.

Yes, you can definitely improve, there is no magic pill, just get yourself into social situations with crowds, try to open out and learn from errors, you may stumble sometimes, you may embarrass yourself sometimes, but none of them are going to kill you.

You can even use your embarrassment as funny stories later.

But don't wait to work on your social skills and then pledge, use this exposure itself as a tool to increase your social quotient.

Make and surround yourself with some understanding friends but relatively more extroverted people. It can help.

Good luck.