The earlier you start finasteride the better. Plain and simple. Don't puzzle your mind with these troubling questions: will this happen, will that happen?
If you plan on using finasteride eventually then for god sakes get on it now. It's easy to dissmiss hairloss until it gets really bad but then at that point you're in quite the pickle!!!!
RAMBONER
ps: been on finasteride for 3 months, no sides, more hair, less worries.