changed steering rack boot today - reset tracking

[benn5150]

I changed the steering rack boot today as it was split. I counted the number of turns it took to undo the track rod end, and did it back up the same number of turns, but now the tracking is off as steering wheel is not level when going straight ahead. Is it gonna be difficult to get it right, or do I need to get it done at a garage. Did the work myself as can't afford to be paying out money for garage labour.