1 year of doing something = plus one level in that stat.
If you're 14 years of age, you are level 14.
If you have $100, you get one level in money.
If you've driven a car/jeep/bus/van etc. at least once, you're level 1 in driving. If you've been driving since you were 15 (legally) and you are 18, you are level 3 in driving.
Basically, I am
Level: 14
Money level: 3
Driving level: 1
Cooking level: 3
Computing level: 3
Education level: 10
Weight level: 14 (your weight in pounds divided by 10 [round it up])
Height level: 17 (your height in cm divided by 10 [round it up])
Please add more. I may decorate the thread a little if people like this.