I think the rule for FHA is that you can only have 1 FHA loan at a time. I don't think FHA in itself is a first-time-homebuyer program, though it may often be "packaged" with a FTHB program by lenders.
It's interesting that you "proved" you weren't a home owner in the past 3 years with tax returns. Wouldn't that just prove you didn't take the mortgage deduction (or any other tax benefit) in the past 3 years? If so, that would seem to mean that if you owned a home free and clear (i.e. paid off, no mortgage) you could qualify as a FTHB?!?! I would think they would do some sort of title search to make sure you didn't have any titles in your name.