Shoe size

So my baby just turned 1 last Friday. She has really small feet. She was wearing newborn shoes up until 5/6 months. And then at 6 months she started on 0-3 months size. Her feet can’t really fit 6-9 months they fall off. She has uggs boots that are 6-12 months and they slip off easily also. So she basically does not wear shoes at all.

Now that she is older and is also walking I want her to wear shoes so she can be comfortable in shoes, especially if outside finally opens back up. I see a lot of infant size 3 and 4 shoes online but I’m not sure if it’s too big or too small. Since we’re unable to go to the store to buy them I’m looking online.

Does anyone have any idea on shoe sizes?

Her feet