I'm shy and reserved, this has affect my life greatly. please help :(?

Being reserved and shy isn't a Good thing at all. i want to be more outgoing .when ppl talk to me ,i just reply with afew words, not more than nesserry even though theres a lot in my mind that i want to speak out n do but i just don't have the courage to do so. I'.m 16 now ,am i going to be shy like this forever? give me some adivice? :( and plus i seldom stand out for myself