Ok, let me give you some advice. Don't take this to heart because I am a 13 year old with no life experience, this is entirely based on my perception of relationships and human behavior.
Don't wait. There is no "perfect moment" to ask someone out. Anything could happen that would keep you two apart. She clearly already knows how you feel, so asking her out might be harder, as typically the surprise of "omg this person likes me" makes them consider you more positively, but if they've had lots and lots of time to think about being in a relationship with you, knowing you like them, the outcome might have changed, especially from the arguing you guys were doing.
Also, remember getting angry and depressed is counter productive. It will only cause you to get angrier and more depressed. Try to control your emotions as much as possible.
If all else fails, remember there is no "one true love". There are most likely several million women that you would have a healthy relationship with. Statistically, there is a good chance you will meet your love. So chill. Be yourself, you are a rational and (seemingly) noncreepy person.
