i need advice on my maternity photos...im doing them with my fiance and his son who is 14...i kinda…

i need advice on my maternity photos...im doing them with my fiance and his son who is 14...i kinda wanna wear a long pretty black dress but we're doing like a rustic scene like at railroad tracks and infront of a silo we have in our front yard...my fiance and his son will probably wear cowboy boots and just nice shirts...do u think the dress will be ok if they wear a black button up too? heres an example of the dress