Codka la wadaago

AITA for telling my SIL that her opinion isn't more important than mine? so a bit of context, i (24F) am getting married in september. i love that month since it’s kinda between summer-fall ish. anyway, my fiancee (29M) proposed to me last december, on my birthday. i’ve met his family countless of times, my future MIL, FIL and SIL. they are all very cordial and friendly. well this mess started when i began organizing my wedding, which is very tedious but really exciting. we hired a wedding p