https://www.cbr.com/how-old-golden-girls-ages/

After endless speculation, the real ages of Dorothy, Blanche, Rose, and Sophia have been revealed, and they're not what most fans believe them to be.

“Sex and the City” star Kristin Davis shocked to learn how old “The Golden Girls” were: 'I thought they were 80' (https://www.yahoo.com/entertainment/articles/sex-city-star-kristin-davis-140000762.html)

The discovery was made during a discussion on Davis' podcast about how people often compare the two female-led shows.

Most of those are believable, but Dorothy is a few years off by my count. One of the few consistent facts in a show full of inconsistencies is that Dorothy and Stan were married for 38 years. If they were married from 1946-84 and got hitched right out of high school, that would mean Dorothy was born in 1927 or 1928 and would have been 57 or 58 in 1985.
55 for Rose as stated in the episode where she was job hunting seems accurate.
I always just pegged Blanche for 50 when the show started. And Sophia seemed to be 80 at the start, so born in 1905 and making her 87 when the series ended.

How Old Were The Golden Girls During The Show (https://screenrant.com/how-old-were-the-golden-girls/)

Watching The Golden Girls today only makes the brilliance of the show more obvious, but viewers might be surprised to learn the actors' ages.

Nicole Kidman and Sandra Bullock (https://twitter.com/emmylanepotter/status/2044406307910820241) are now the same age (https://www.google.com/search?q=Nicole+Kidman+and+Sandra+Bullock+are+now+the+same+age+as+the+cast+of+%27The+Golden+Girls%27&sca_esv=09e795cc6b8f4569&biw=1235&bih=547&sxsrf=ANbL-n6ikeizPRBXbBCd2ql3rndqDbRZUQ%3A1776289745600&ei=0QfgaeKbJIGh0PEPzcLpQQ&ved=0ahUKEwiiyLf66vCTAxWBEDQIHU1hOggQ4dUDCBE&uact=5&oq=Nicole+Kidman+and+Sandra+Bullock+are+now+the+same+age+as+the+cast+of+%27The+Golden+Girls%27&gs_lp=Egxnd3Mtd2l6LXNlcnAiV05pY29sZSBLaWRtYW4gYW5kIFNhbmRyYSBCdWxsb2NrIGFyZSBub3cgdGhlIHNhbWUgYWdlIGFzIHRoZSBjYXN0IG9mICdUaGUgR29sZGVuIEdpcmxzJ0i5BlDQAljQAnABeACQAQCYAWigAWiqAQMwLjG4AQPIAQD4AQH4AQKYAgGgAhOoAhTCAhAQIxgnGOgGGOoCGJ0GGN0FwgIHECMYJxjqAsICDRAjGPAFGCcYyQIY6gLCAhcQABiABBiRAhi0AhjnBhiKBRjqAtgBAcICEBAAGAMYtAIY6gIYjwHYAQHCAhAQLhgDGLQCGOoCGI8B2AEBmAMT8QXv5B41W8UsAboGBggBEAEYAZIHATGgB5UBsgcAuAcAwgcDMy0xyAcRgAgA&sclient=gws-wiz-serp) as the cast of 'The Golden Girls' :crazy:

It's pretty easy to tell the girls were supposed to be in their fifties as they were still working. I know Bea and Betty were in their sixties. The show made it pretty clear that Blanche was the youngest.