dont tell her you love her until you know you can handle even the worst parts of her. dont tell her you love her until you know you are mature enough to follow through. the right time can be in two months, or two years. It all depends on where you two are at. but love is more than a feeling, it's a decision to commit and to handle all of her human flaws. You need to know what you're getting yourself into.
Too many guys throw the word love around believing that it is just about the feeling and nothing else. But it is so much more. Don't be that guy. Don't make that mistake. Love is a mental thing as much as it is an emotional one. It requires a LOT of strength, and it requires you to trust and respect her fully. Wait until you two have had a few fights, if you still love her, then tell her. If you are not sure, there is nothing wrong with talking to her about it. Ask her what she thinks about love, her answers about love might make you come to certain conclusions as well. But in the end. Don't tell her you love her unless you are willing to put up with all the shitty parts of a relationship.