20 month old crawling instead of walking?

Ch

Hello

have a 20 month old. She's been walking since about 11 months.

All of a sudden, the last few weeks or a month, she's been crawling everywhere. Or will start start walking and go down to her knees and crawl the rest of the way. Crawls alot around our home, etc.

Is this normal or something should bring up to her doctor?