1) it needs to grow to sufficient maturity
2) if you are growing it in Canada, growth rate will be retarded by anemic growing conditions outside during the warmer months and even less ideal conditions indoors during the freezing months, as well as from being a tree grown in a container.
3) once/if at full growth, it may need flowers/pollen from a second tree to cross pollinate.
4) even if flowers are pollinated, growing conditions may not support mango fruit to ripeness
5) even if fruit grows and ripens fully, being grown from seed, the fruit likey will not have the samemcharacteristics as the fruit you obtained the seed from
Even so, the little 3 ft mango tree I have is quite handsome and makes a nice houseplant. Now I have another 1 ft baby tree and an 8" one as well.