This is my first bull run over the next few years so I am just wondering when do altcoins usually start really pumping, is it long after the Bitcoin halving?
Congratulations on the increase in value in your portfolio, mate. Then, referring to the title of your topic, alt season actually occurs when the Bitcoin Dominance Index is smaller than Altcoins, that's what we call alt season.
So the Bitcoin halving has no correlation whatsoever with alt season, BTW, to see Bitcoin Dominance Index you can see it here. I hope this helps.