[at an early age] or [at their early ages]

My grandfather learned to play the piano between four and six. My dad learned to play the guitar between five and eight. My uncle learned to play the flute between four and nine.

I have made up the sentences below about my family members who learned how to play music.

(1) At an early age, my grandfather, dad and uncle learned how to play a musical instrument.

(2) At their early ages, my grandfather, dad and uncle learned how to play a musical instrument.

I am not sure which sentence is correct. Please help me. Thank you very much.