Would you be concerned?

My 12 month old daughter doesn't crawl or walk. In fact, she doesn't roll over anymore either. She did when she was younger. She scoots everywhere on her bottom. She gets all around the house. She acts like she is afraid to try to walk alone. We encourage her by holding her hands and letting her walk and try to get her to take a couple steps to us unisted. She has had a lot of ear infections and is getting tubes put in this month. I was thinking maybe that has something to do with her balance. My other 2 kids were late walkers, 16 and 17 months, though they crawled by 11 months. She can say some words and know quite a few things from animal sounds to body parts. I am hoping she is just learning academically and will physically catch up later. Anyone have experience with this? And what was the outcome?