Quick question about birth control pills

Leana
So I just started the pill yesterday my doctor told me that if my period started on a Sunday start taking them then but then if it didn't start them the Sunday after your period starts. So mine started on Thursday and they've always been 7 days never any less and sometimes more but I'm just wondering since I started the pill yesterday will it make my period end sooner than my usual seven days? (Also today it was very light)