It may be sad and cynical, but if you truly are madly falling in love for a girl, the worst thing you can do is tell her too early.
Women get scared and run away faster than men do! And women need more time to analyze the situation and allow for their feelings to develop.
Women at this day and age are much easier to jump in the sack with you before they have feelings for you than MEN are, i truly believe.
Do not make the mistake of letting your giddiness and joy from finding her and feeling the joys of love make you jump the gun on somethign like this.