Hi.
Love is a strange thing.
And love is a highly, highly personal thing. Some people may want to tell someone they are casually dating that they love them while some people take years to be able to tell a person they are romantically involved with that they love them. So I would have to say that most everything rests on what it means for you to say "I love you."
But you might have decided this is the person, this is the time and you still feel afraid. Your fear could be completely normal, or it could be a sign that something is not quite right. You may want to spend more time thinking about where you fear is really coming from.
If you are going to talk about your feelings with someone else, there usually isn't a "right time," in a scientific or mathematical sense. The best time to talk about your feelings for a person is when you feel comfortable with the idea of talking them over, whether that comfort comes from confidence in your strong feelings or from knowing that your friendship with the other person can survive whatever might happen.
The flip side of love is rejection, and sometimes rejection can be an extremely painful thing to experience.
And if you get rejected? That rejection may be the other person pulling away from you. It could also be that they are not ready to say they love anybody at this stage in their life, or at this stage in your relationship.