There isnt a limit to number of talents.
If you run a longer term campaign I recommend making additional talents cost more
Otherwise it gets too easy for players to collect all the good talents.
For example something like the first talent they buy is 10, second is 15, third is 20, etc...
You can do the same thing with skills and make skill advancement cost more the higher the skill theyre trying to advance is.
The reason I prefer doing that over just awarding less XP is because I like to award consistent amounts of XP. I dont like doing the silly questions thing because once people learn the questions they try to game the system. Making extra talents and higher skills cost more also encourages players to spend their XP differently, theyll often spend it on putting points in skills they dont have yet, instead of spending it on talents and maxing out a fewer number of skills. Making it harder for players to specialize helps keep the dice pools smaller so things dont become too easy for the players.