Crypto exchange business is a tough business that requires too many stuff. From development to features to graphics to design to marketing to security. People with millions of dollars invested into it with a huge team still could fail at it and they do, look at places like kraken and poloniex that used to be something but now failing horribly and they are huge business' that fail.

Hence, if you want to start your own exchange at a young age know that it is quite hard to break into that business and almost impossible to make profit while running it as a one man operation. You would need experts of all topics mentioned above and you  would need a lot of capital to do your own marketing as well. If you do not posses the capital and man power for any of that I would suggest not to bother with it.