Obviously if you do it too soon you are too forward and that is bad. If you take too long she might lose interest.
Most Helpful Girl
it's true the window of opportunity closes... nobody likes hello and then would you like to go out with me... then there's the guy you know for months then he asks by then your thinking okay what am i his 5th or 20th choice? usaully i help the guy by giving a very subtle hint like a restaurant i love or kind of food... and if they don't get it then they're dense... some are... and it doesn't make them bad people just dense people.2
Most Helpful Guy
After 20 minutes of conversation you can ask them out. You don't have to call it a date or anything either. Just be like "you know, I really enjoy talking to you, If you're free this weekend we should grab some drinks and hangout together."
They'll either say they're busy, or they'll give you their number then say they are busy in text. OR they'll say OK and you guys out for drinks.
Simple as that. If they are into you as long as you don't fuck up anything major it'll be alright. If they are iffy about going out with you then it's not worth the effort in the long run anyways.0