90 days old? Looks healthy and all but id think 90 days of growth it wouldve been bigger than that. I've got some super Cali haze super auto growing they're supposed to run 120 days. What strain is that your growing??:D
Does sound like your overwatering . try waiting til soil is bone dry first couple inches. Or pick up pot to see when it feels lightweight before watering again.
how many "actual" watts on those cfl's. Don't believe that's enough light for that space either imo. cfl's only really penetrates 5-6" i use them for supplemental side lighting and early stage seedlings .