Meet up face-to-face. Find Bitcoiners in your area and I'm pretty sure there would be people interested in purchasing Bitcoins off you. Else, you can find someone on this forum that will do mail in cash for BTC for you.

An example of a platform that does this is localbitcoins and they have a pretty good escrow system.

I want to surprise my parents so they can't know about it which means I can't use a bank account, I will look into debit cards, thanks.

Well I guess I'm lucky since our capital has a few of them and it's only about 15km from where I live.
How exactly do these work? I just send my BTC to their address and it prints out cash?

Since you're underage and you are already aware of bitcoin then in my opinion, you are really smart than those kids around there. Why not use localbitcoins.com if you have one in your locality and ask one area brother to join. You can use his account or ask him to follow you for a tip but be sure he is someone to be trusted. Doing this might save you a lot of troubles because parents might not understand.

I have new idea how you can withdrawal your money.Explain to your friend how bitcoin works and then teach him how he can earn bitcoins online and he will be suprised maybe or maybe not try it maybe it will work and then offer him  to sell some amount for bitoin and explain him how he can turn that amount of bitcoins to bigger amount of bitcoins.So first he need to pay you via fiat cash and then you can teach him how he can create bitcoin wallet or try to find person from your town which accept bitcoin -fiat exchange and then change but they will earn a little money on you because you get less fiat money whe you exchange with some trader .

i think it would not be your friend because your friend is the same age like you so you need to explain bitcoin to your dad or people which is older than you and after that you can find buyer in localbitcoin or other place and make negotiate with the buyer using the account from person that is older than you. when the negoatiate is deal, then the buyer can send the money to person that older from you, you send the amount of bitcoin to the buyer.

Well then hook on to an exchange and get them to send you fiat by mobile money or buy something online with your Bitcoin and then pawn them for fiat afterwards but I'm wondering why would an underage be needing that extra cash for if your parents are that responsible in keeping you off Bitcoin/money.

Localbitcoin or bitsquare is the fit for you, localbitcoin meet bitcoin trader around you, use escrow to secure your transaction.
Bitsquare is an exchange platform which decentralized system, don't need account, don't need an identity.

Luckily I have my local exchanger that able to withdraw/convert btc into fiat without using ID at the moment

They using ID only for verification purpose and able to chat each other. Other than that , nothing is important !