If you have no preferred pronouns, just say (none) or something
This will help make people feel more comfortable in this comm and has a side effect of showing you support trans people when making comments in other communities. It will also make reactionaries seethe and make it easier for mods to purge them, and make trans people feel safer all over the fediverse.
There is a limit to how long usernames/nicknames can be on lemmy. You might have to only do like NOOBMASTER (she) or some shorter nickname for it to let you save it.
I guess you were right, thanks!