Ehh, it's not too bad for a first raid, but compared to other raids you're likely to get very overwhelmed by it as the main mechanic of the raid involves a lot of symbols and a lot of communication.
Vault of Glass would be a better first time experience if you don't feel too confident but would like to get more teamwork experience, if you do go for Vow as your first, look up a chart of all the symbols so you know what to shoot/look for.
I think though that there's definitely room for just ad clear for a 1st timer so they wouldn't need to know all the symbols by heart....only a few in 1st encounter really depending on role