One of the Olympic legend's daughters, McKenna, shared the good news on her Instagram page on Monday ... thanking doctors, nurses and fans for everything they've done to get her to this point.

"We still have a long road of recovery ahead of us," McKenna wrote, "but baby steps."

Retton was first admitted into the ICU earlier this month after contracting a rare form of pneumonia ... and while initially her family was pleased with her progress, they said she suffered a "pretty scary setback" last week.

Seems, though, Retton has battled past that ... something her family is obviously overjoyed about.

"We are overwhelmed with the love and support from everyone," McKenna said. "Grateful doesn't scrape the surface of the posture of our hearts."