The Jolly Jumper instructions say that you can use them from 3 months of age as long as they have good neck control. I used ours when our boys were 4 months old and they loved it. Just make sure you position it so your DD's feet are flat on the floor and she's not on her tippy-toes and don't use it for long periods at a time. I used to use ours for up to 15 minutes at a time and only a few times a week. Neither of my boys have had any trouble with walking normally.

The walker that doesn't walk is called an exersaucer! They are fantastic, I used one for DS2 and it was a great way to entertain him when he was getting bored or gizzly. I highly recommend them! The only problem is that they are quite large and take up heaps of room and you have to store it somewhere when she's grown out of it. Something to consider