Waking up too early can be a sign of Insomnia.
Even if you can easily fall asleep at night without sleeping pills some people who do suffer from Insomnia only wake up too early.
If you're waking up too early then you may need to take some over the counter sleeping medicines to help you stay asleep.
Or if you continue waking up too early you should speak with your doctor.
You can also try standard sleep hygiene practices, relaxation exercises, mindfulness meditation etc to help you fall asleep fast and stay asleep.
Also try going to bed the same time each night which gets your body into a routine where your body gets used to going to sleep at the same time each night as well.
If you do wake up too early then try staying in bed and continue to sleep by keeping your eyes closed.
As long as you're getting 6 to 7 hours of sleep per night you should be okay even if you wake up too early.