You should wait until you are sure that you legitimately feel LOVE for this person and not simply infatuation or strong attraction. Make sure you're ready for commitment.
This is a tough question because the answer is different for every couple. I recommend you do not say it unless you feel the other person feels the same way.
I get the sense that it's pretty soon, since you said 'I already feel it". If that's the case, I would wait a month or so and see how it goes. You can normally tell how someone feels about you, so I'd gauge it by that.
Typically, you say it when you feel your partner feels the same as you do about the situation. You openly discuss your love when the feeling is mutual.
This varies tremendously from relationship to relationship, and there is no set answer. It is inherently awkward. Don't do it for at least the first month or so, however.
At least one year later, you had better wait for him/her to say that first,then you will know exactly the feelings between you two.This three words also have deep meanings and saying them is not a joke.
