When does pivoting in circles progress to crawling?

[TwizMoo]

My 7.5mo old can't crawl but drags herself round in circles on the floor with her hands to get about. She seems frustrated that she cant move forward.

Just wondering if this is normal and how soon she might be able to crawl forward?

Thanks

Bump

The circling is definitely normal, but I'm afraid how soon it will progress to crawling is a 'how long is a piece of string?' question. For my daughter, it was something like 4 months, but that's because she tried to miss out crawling and go straight to walking. She was cruising the furniture starting about 2 months after the circling, and it took another 2 months before she conceded that crawling had its uses. I'd assume most are faster...

My 10 month old has been doing it for two ish months now
Still no crawling