I just switched my daughter who is 7 months, she's getting too long for her carrier. Their heads shouldn't be within an inch of the top of the seat. I got an all on one seat that doesn't expire for 10 year. It does rear,front, and high back booster. I got the graco milestone and I love it so far. Decently priced too.

You can switch to a convertible whenever you're ready, just make sure baby doesn't exceed the either limits in the newborn seat though. You want to rear face til two, closer to 4 is great! most convertibles rear face till 40 pounds and that gets most babes till 3 or 4!! it's 500% safer and less risk of internal decapitation in a forward facing car wreck😊

I had to switch to a convertible car seat when my daughter reached 5 months. She was too long for infant. Convertible can be forward or rear.

look up extended rear face car seating and then it'll show a variety of next step seats that you can use...

there should be a weight and height limit written on side of carseat