You have to startup something – to find out where it might take you. The secret is not so much in the idea – but in the starting.
That coupled with a inquisitive mind and as you create, succeed and fail; create succeed and fail; over and over again, so you will find out what is possible.
Yes, TS Eliot said it perfectly – if you aren’t in over your head, how do you know how tall you are?
Except, of course, that you are still growing…