perhaps you are a light sleeper, yep.

perhaps your body is just used to getting up at a certain time each day

perhaps you need a new matress? (I hear it's a good idea to replace them every 4 to 8 years)

perhaps you have some anxiety about something- or other thoughts

perhaps it's the light from outside waking you up? (do you sleep with the curtains open in summer, for example)

their are some thoughts... good luck