Look in the glovebox. There's a little book there called: Owners Manual'. Each and every answer you could ever want to know about your car are in there. But generally speaking you should change your oil between 3,000 to absolutely no more than 5,000 miles.
Just because you're a girl doesn't mean you shouldn't know when to change the oil in your car! There are some factors in determining how often you need to change the oil: 1. Make, model and age of the car 2. How often you drive the car 3. Temperature of the area where you drive However, the generic answer to your question is it's recommended to change the oil every 3000 miles OR after 3 months. Your car's owner's manual should give you a proper guideline. Good luck!! AND, stop using the fact that you're a girl for not knowing things :)
it depends on the grade of oil. some are coming with synthetic oil. in which case the interval can be 7500 mi. for every oil change. Honda motor company studied the subject extensively and have change there interval for regular oil interval to 7500 mi. because of risk to the enviroment of producing and disposing of so much oil worldwide. The advice I could give is as often as you think about it change it, because when oil is new it holds up to the heat better. When it gets older it will break up and deposit in the oiling system and cause major issues. The oil produced in the modern era is better than years ago because of filtration and oil processing. this was Honda's main argument for changing their interval. so if your car is driven more than 15 mi everyday to permit complete engine warm-up it can longer between changes. if it sits for weeks or months at a time when the oil can not warm-up the change should be every 500 miles or more. due to moisture build up.
Just to be safe i do it every 3,000 miles and i have a higher mileage car so i use the best high mileage oil i can get. But i also have a turbo so my oil is more important than someone that's naturally aspirated.