I told my ex I "loved him but wasn't in love with him" the first time he said he was in love with me. However, we were 17 and had been together for 6 weeks. What did the joker expect?? I think he only said it to get something truth be told.
However, I have fallen in love in less the x amount of months, so I do know it can happen. Years though? Nah. In the immortal words of the Blue Notes, "If you don't know me by noooow..."