Seats for baby?

My 3 month old loves to sit up and not so much lie down for very long when she's awake (like in a swing or even on the floor) does anyone have recommendations on seats for her? She always tries to sit up because she likes to see everything going on, but obviously, she can't just sit on her own and still needs support. She was also born 6 weeks early, so her posture is still behind what it should be too. I've heard good and bad things about the bumbo, so I'm not sure about it. But any other recommendations or what you all are using?