Yes, it is very normal for your first period. This exact thing happened with my daughter too. Your body will spend the next year getting used to having your periods and some may be light and some may be more. They also may not fall exactly the same days apart this first year. You may want to get a calendar and start keep track of when they each start and finish so you can know what to expect and also to know how your body is working with your period cycles (the amount of days between each period). Don't worry. Everything is fine.
Now that your on your period, be careful around guys, as now you have a chance of getting pregnant, my friend sadly wasn't smart enough, or didn't get the advice fast enough not to have sex, as she got pregnant at 14 :/
also remember that ESPECIALLY in the first year of your period you may not have a period every month. this is also common. mine did not start coming every month until my late teens. i still cannot track my period by days and i am 44.