After scoring four goals on his debut in City's U15's side, Robertson's star has only continued to rise with four countries now battling for his signature.
Australia, England, Peru and Scotland all have connections to the former Hakoah junior, who admits he's yet to decide which one to represent.
"I'm gonna get to a point where I have to make a decision," Robertson told Optus Sport.
"There's a different gut feeling about every country.
"Australia - I've lived here, I'm from here. Scotland - I was born there, my grandparents were born there. Peru - my mum, my grandma, my great grandma, her side of the family is all Peruvian. England - they've taken me in as a country."
With that big decision still to make, Robertson revealed former Liverpool and Real Madrid striker Michael Owen has given him some sage advice as he looks to carve out what could be a very successful career.
"Michael's my agent, but he's more so a mentor to me," he said.
"He gives me advice, we obviously speak on a daily basis or every other day.
"But he just says 'enjoy being young, enjoy your football, because when you start getting paid - that's your job'."
Robertson, whose father and grandfather both played for Australia, also described former Socceroos Lucas Neill as an uncle while growing up.
Watch the full Optus Sport feature on Robertson below.
Grandad played for Australia.— Optus Sport (@OptusSport) March 28, 2019
Dad played for Australia.
But 15-year-old Alexander Robertson, who chose #ManchesterCity over the chasing top six pack, will soon have another tough call: his international allegiance.
The family discuss that & more in this #OptusSport feature. pic.twitter.com/HZs90ApU5z