I need help with a week old kittens?!?

My kittens, as of today, are 6 days old, and up till now, they were always fine with staying in a cage with their mother, but today, after nursing, when the mother came out for a snack, the kittens crawled out, (for the first time) and went to the mum for feeding again. Is it normal for cats to start crawling this early? They can't stand up properly though, and their eyes aren't opened yet. When will they start eating solid food, standing and walking and open their eyes??