You're talking of 20 miles/week. Put like that, it doesn't sound so unobtainable.
Can you cycle to your course (college, uni - whatever) ?
Can you cycle to your hockey practices ?
Can you cycle to the shops ?
Can you cycle to the pub
?
Can you think of any other occasions you could use your bike during the week ?
These could be 'bonus' miles or 'bonu
'.
Your 1000 miles don't necessarily have to be in big blocks, do they ?? Even 5 miles/day would give you the distance.
As Rod said, if you have been coaxed into it from a young age .......... you've taken your time
but it's never too late