There are 3 well known musicians born the same year as me. Prince - a slew of half siblings that were older than him. Madonna - she has older siblings. Michael Jackson - his charm was that he was the baby of the group - several older siblings. And, of course, me - my one sibling is an older sister. As kids, she was the better musician. As adults, I’ve passed her through persistence.
Other notable musicians that come to mind - Bruce Springsteen - first born. Paul McCartney - first born. John Lennon - youngest of 4.
The Gallaghers - Paul, Noel, and Liam - all musicians, but the first born - not sure of his ability, but the least known of the 3.
I don’t believe first borns have an advantage here. Seems pretty random to me.