AITA for casting an aoe spell that hits a party member?

So we ended up in this graveyard and awoke a skeleton lord and his horde of zombies and skeletons. I had the opportunity to cast reverse gravity and likely get almost all of the low level monsters killed in the first round but it meant that 2 party members were also going to be caught in the spell. We are all level 13 so I knew they had a decent chance of making the save and even if they failed the damage wasn't serious at that level. It ended up only one of them failed and took some damage while I managed to kill almost all the creatures on the field. Is it just bad form to cast aoe spells that might hurt players without getting their permission first or do you think the one guy who failed his save should have just accepted sometimes it's unavoidable.

Also I do have feather fall but my DM won't allow me to use it on people I reverse gravity because he thinks it makes it too overpowered.