Forget about upgrading your front derailer if it works if it doesn't work that great check the set up I bet that will make all the difference. As others have said get some new wheels and tires if u feel u need to upgrade the bike then when u do grow out of this bike u can use them on your new bike. If u don't have it a computer would be nice as well as a good pair of cycling shoes and peddles. If u already have those thing get some new cycling clothes u can never have enough. A good bike fit is also a good idea as well.