It doesn't matter who says it but I would say a few months maybe. It really depends, I say you should say it when you know in your heart of hearts that you truly feel it. Do not say it because you are clingy or needy, say it because this person is your friend, cares for you, is there for you, stimulates you and all this has been happening consistently for a good while. Do not jump the gun, let it flow and come out when it is ready to.
r0yal