Nobody is saying you never have to try to improve or grow as a person, but it's always important to be your authentic self, especially if you are looking to meet new women. One of the best things about relationships is that you're supposed to love each other for who you both truly are, so if you enter under a false personality, it could be your undoing in the end.
If you don't love all of her hobbies, don't pretend you do. If you're a bit of a dork, don't try to act cool all the time. If you're terrible at cooking, just admit it. Women love when a man is comfortable with who he is. You'll also be a lot more relaxed and fun to be around if you aren't worrying about trying to impress anyone.