Chances that this girl's number will lead to anything long term is about 1 in 10, and even if it is that 1 in 10 and it becomes marriage, there is then a 1 in 2 chance that it will fall apart and you will lose half your money plus your legal fees, so in essence you will lose more than half of what you have, plus all the money you lost during the dating/wedding phase.
So, a 10% chance you get by step one, and then a 50% chance you stay for life, so there is only a 5% chance that calling this girl will be lead to something good for you for the remainder of your life.
Save your time and your money, don't become a free meal-ticket for that girl. Instead of calling that girl, call an older man in your neighborhood or a male teacher and ask him how his life is going. All the older guys I know like teachers I've had or parents of my friends, guys that are 55 and older are telling me the same story; don't do it. It just turns to crap no matter what you do. They'd rather be independent. At best it's a tedious bore. At worst a living hell with financial ruin thrown in for good measure. The problem is that when you're young, you just naturally fall into this mind set where your whole self image is based on how women regard you, and so you spend all your money and energy trying to make yourself acceptable to them. Then later in life the shine wears off and you finally realize that you've wasted yourself on a bunch of crap.
A huge percentage of girls are selfish, flighty, insecure, needy and psychotic, and quite capable of concealing those traits during the dating phase. Even already you are falling into their games, wondering how many days you should let go by before you call, screw that b****, let her buy her own food, pay for her own movie and pay her own house/car payments. Call an older man in your neighborhood (and make sure his wife is not home when you call), he will tell you the truth, and after he tells you the truth, you will never ever even think of calling this girl you currently seem interested in. Or if you're too embarrassed to call an older man in your neighborhood, just call 1-800-Flowers and buy your mother a nice bouquet of roses, she will never ever backstab you, drag you to court and take half your money away and play mental games or phone games with you.