Baby bath seat

Emilee

My six month old girl is getting too big for her bathtub. We only have showers, so we will need to purchase a bath seat to go in the shower. Any recommendations? I am afraid to buy one and it be too small, as she has a chunky butt and legs.

If it helps at all with sizing, she is in 9-12 month clothes, 18 pounds and wears a size 4 diaper.

Thanks in advance!