Jehovas Witnesses outfit advice needed

(sorry if i offend anyone im not trying to i dont know how to word some things)

my boyfriend is wanting to get back into the religion or community im not sure if either wording is correct. anyways his mom wants him to go to a special talk this month as well as a commemoration of Jehovah's death. i think i said that correctly.

anyways he wants to take our son and i. We are going to go shopping tomorrow to geg me something to wear since tshirts and pants wont do. hes going to wear a suit and ive seen how his mom dresses but i dont know what to wear.

if someone could comment outfit picture ideas that would be great. i want to make a good impression but also dont really want to dress like an old person im only 19 and i want to feel good about myself especially after having a baby. are there any tips or rules i need to follow when picking something. also im not that into dresses but im willing to try. i also only wear boots so thats going to be interesting to try and find shoes i hate flats and anything that shows feet. and i cant walk in heels.

someone please help