They are both just cantrips, and will not have a major impact on playing your class, generally speaking.
What was the source of your cantrip? Since you're saying that it's just one, I'm guessing it was a freebie from your race choice? What class are you playing?
Minor illusion, as it exists in the game currently, if functionally just a 'turn that npc/monster around' spell - but for friendly NPCs, they usually turn right back again after a short moment, so it's not really useful for things like pickpocketing. It can be useful for setting up a backstab for an ally, but generally not for you, since it's an action to use it.
Bladeward lasts for a couple of rounds and gives you resistance to bludgeoning/piercing/slashing, which covers most mundane weapon attacks; it's also very limited in usefulness, since it's more often the case that you'll save more damage overall by using your action that turn to do something else to kill or put down an enemy.
Both have situations where they'll be useful to cast, but overall those situations will be few and the impact relatively minor; it's probably not really worth restarting your game over, if you're out of the intro.