Wizard Charactermancer only letting me choose 3 0-level spells

In character creation, there are only 3 slots for wizard cantrips, even though the rules state that wizards begin with all sorc/wizard cantrips in their spellbook (save for opposition schools). How do I fix this?

The rule for wizards is: At 1st level, you know three Cantrips of your choice from the Wizard spell list. You learn additional Wizard Cantrips of your choice at higher levels, as shown in the Cantrips Known column of the Wizard table. This is followed by Charactermancer. Where are you seeing the rule you cite? It sounds like homebrew.

It says right in the spellbook class feature that you begin play with a spellbook containing all 0-level sorcerer/wizard spells excluding those from your opposition schools.

Oops, forgot to mention that this is Pathfinder. Don't know how it works in 5e. The charactermancer for pathfinder says I get all cantrips

Ah, That makes a huge difference. :D I'll let a Pathfinder person answer this. PF1 or PF2?

This is PF 1

While you do technically know them all, do you really need to have them all on your sheet?  If you load up every spell all the time, you can get to the point where your sheet loads very slowly due to all the extra attributes and entries that the sheetworkers interact with.  That is why it allows you to choose however many you can actually prepare at a time. You can drag out others from the compendium after the character is created, but I personally would advise not adding every cantrip just because your wizard knows it.  If I am counting right, if you add all the cantrips in the compendium and then add all 1st party spells, you are up to a possible 30 cantrips, before you get to any 3rd party content that may be allowed in your game.  Be honest, how likely are you to actually prepare Bleed?  If you aren't likely to ever cast a certain spell, it is best to just not have it on the sheet.

Ok, thanks! As long as I can get them later, there is no issue! Thanks for clearing this up.