Dont worry bro, if your heart say buy and your wife support it. Go for it. You dont have to use the car for 9 years. Over the time, when u feel need to change the car, just do it. If i do have stable income 7-9k per month, i sure buy cause i like bmw also.

as for the services etc, when u bought the car, you will feel obligated to save, so no worries, it will comes later.