It was my little dream to own 21 BTC and today i achieved it after hard work of so long time.Now i want to make my hard work pay me.I mean,i want that these bitcoins work for me someway and grow.Is there bitcoin bank that pays interest? What will you do with 21 BTC? How will you spend it? How will you grow it? Share anything you want that may help me to decide what should i do. 
I will keep holding on to them because i do not see any reason why I would spend them of sell them all right away. I am going to wait for the right price and then I will sell some but not all at once because that is not smart.
Saving them for future is an good idea, but I think some of them should be invested in trading so that you can grow them over a period of time and if everything goes fine with you then you can hold higher number of coins.