I wouldn't underestimate people, just because they are a different age than you are. I know people who have come out to family members in their 80s and 90s and been accepted better than by people much younger. Also I have younger friends who are accepted by grandparents and not at all by parents. A lot of older people have been thru a lot and are able to put things into perspective.
I am an older person who has come out, my friends and acquaintances had no more trouble with this than I hear about from other people.
OTOH, what would bother me personally is not their age, per se, but that there are so many of them. 370 people in a work place (even if, I understand these are the clients) is a huge number of people with a lot of different potential beliefs. The weights are the same as other types of situations, imo, getting misgendered, explaining your situation, etc. etc. But age, per se, imo, is not the main factor.
--Jay