Frankly you should keep on playing cricket, giving in your best effort and not think why you wont make it. You should think you might make it. People who have made it are made of blood and flesh, same as you.
Example 1 : Sachin Tendulkar showed emmense dedication and worked on his cricket as much as he could, even staying at his uncle's because the ground would be closer from there, playing 2-3 matches a day when possible, practising even after a hard day's cricket.
Agreed Tendulkar was the most gifted of cricketers but his work ethic is some thing you can only learn from and try and emulate. Dont ignore your studies but play as much as possible
Example 2 : Saeed Anwar never played cricket seriously till he was in college! So forget the examples of Graeme Hick. Remember its never too late to start. Keep trying
One thing which would help would be to be a very good student of the game. Read the art of cricket by Don Bradman if possible, keep talking to coaches, fellow players and seniors to improve your skills.
You may not make it and there would be no shame in that. A lot of great West Indies players played little or no cricket for the West Indies during the era of the pace quartet. A similar situation is prevelant in Australia right now.
Keep trying and keep enjoying the great game. You should aspire to make it to the national team. And aspiring that, you should be more serious on your cricket than what you are and improve your dedication levels. If you dont make it after that, doesnt matter, you would have learnt a lot of skills of an excellent game.