how long when dating can you say I love you to your girlfriend?
whenever the time feels right. the fact that you are questioning should tell you that you love her. if you love her then tell her before you loose your chance, sounds cheesy but it is true. if it has only been a couple weeks you might want to wait.
I'd wait till you'll have been dating for about 3 weeks
The first second, if you believe it is the truth.
When you know it's true love anytime :)
Whenever you feel that you really do love her most. If you're asking the question and you already lover her then I would wait about a month at the most.
when you love her.
When you can say it and know your telling the truth
Well... my boyfriend and I said, " I love you," to each other, on the day we started dating. It does depend though.