McTominay says being a late bloomer can work to his advantage in terms of extending his career.
Recalling being at the club as a 12 year-old, he said in United's documentary, ''I used to have to proper fight, didn’t I?
“It wasn’t easy. You’ve got lads who are fully grown men at 13 or 14, potentially. That’s how quick it can be. And I was a proper kid. But I always fancied myself to be one of the best in training sessions and in games, that was my motivation at the time.
“My dad put very little pressure on me to play for Man United. He just said you enjoy it, you have a good time, I’ll take you three or four times a week, no problem – my time is your time.
“There’s no right or wrong way. You see Wayne Rooney or Michael Owen were playing in the Premier League at 16 or 17, but their bodies take a lot more later down the line. I started at 19 or 20, so my career could go longer. I could play until I’m 37 or 38, subject to injury.”