I've never grown fruit trees before but recently purchased a plum tree (a graft with both Santa road and Stirling) from the local nursery. Spring has sprung here in Aus and it is happily producing leaves, flowers, and the start of some small fruits

I have read that you should cut off the fruit during the first year so that the plant focuses on getting big and strong, rate than loosing energy on a few small fruit, but I've got no idea how old my tree is when I baught it... It is about as tall as I am (kinda average height female... Maybe 1.6m but it's been years since I've measuresd...) so as wondering if anyone had any idea how old this may be? I'm guessing one but honestly, I've no idea!
thankyou in advance!