As a paid member of staff of a charity, a volunteer at that charity and a hospital volunteer I've been on lots of courses on all manner of things, some done in house, so no extra charge, some done by the local cvo, some by the local law centre, some by kindly people who offer free places, some by specialist solicitors
Every time I've done a first aid course something has changed and I have learned how to do things the most up to date way, the same applies to all the other courses, I have always learned something new even if I've done a training before
I recently did a trainjng on unconscious bias run by someone outside the organization and there were others from different places, and it was really good, we all learned from each other. Yes we all have unconscious biases but some know they have and are very careful to learn and others deny that they have.
Its not just a matter of being in a volunteer team which has a Muslim volunteer, a volunteer in a wheelchair, a black teenager, a single mum, a man from a rough estate, that sort of thing, it's being open to learning from the people, or their needs you are likely to come into contact with, or people that need your services but don't come along because they are worried that maybe they'll be looked down on or misunderstood, or that people won't understand that they need different food as they haven't got a cooker cos they are in emergency accommodation. Maybe none of the posters have someone who looks like them, all the photos of families have Dads but their family has been abandoned by the dad, simple things like that
Go along and learn something new, I'm sure they won't force you to share pro ouns, but if someone uses different ones to the ones you think they ought to, it's not a big deal to call them by the ones that they prefer. Think how you'd feel if after divorce people insisted on writing to you as Mrs Fred Bloggs instead of Mrs or ms Anne Bloggs or indeed Ms Anne Maidenname. It's just courtesy really making someone feel like they have been listened to
I'm sure no one on the course will identify as a cat, but you could take a packet of dreamies just in case