Ruling on bridesmaids

It is permissible for the bride to have someone to help
adorn her and accompany her, or a female servant who will serve her, in
return for a specified wage paid by the husband or bride or someone else.
This was widespread in ancient times and is still done in some countries.
It is permissible according to sharee‘ah, as stated above. The fuqaha’
stated clearly that if it is the woman’s custom to have a servant, then
the husband has to bring someone to serve her. 

It says in Kashshaaf al-Qinaa‘ (5/463): If the wife
needs someone to serve her, because a woman like her does not serve herself
or because of her high position, and she has no servant, then she is
entitled to a servant because Allah says (interpretation of the meaning):
“and live with them honourably” [al-Nisa’ 4:19], and because it is
something that is needed all the time. But the servant should only be
someone for whom it is permissible to look at the wife, either a woman or a
relative who is a mahram. End quote. 

Having bridesmaids or a servant is not something that belongs
to one particular culture or that has to do with religion; rather it a
matter of custom or tradition, which varies from one society to another, and
may be necessary. 

And Allah knows best.