Either Carrol is pregnant, or she's experiencing menopause.
Yes you can experience menopause being 20.
"Menopause starts for most people in their late 40s or early 50s. But in early or premature menopause, the drop in estrogen production and the end of menstrual periods comes much earlier. Premature menopause begins before the age of 40, and can sometimes happen in your 20s."
Is what healthline.com says,
And,
"Early menopause can happen naturally if a woman's ovaries stop making normal levels of certain hormones, particularly the hormone oestrogen. This is sometimes called premature ovarian failure, or primary ovarian insufficiency."
Is what nhs.uk says.
Hope it helps! ^^