Credit: Facebook Photo: Leah Messer Hugs Her Daughter Aliannah on March 13, 2013

It's a Memorial Day miracle, people! Leah Messer's precious 3-year-old daughter Aliannah Simms spent the weekend walking around the neighborhood with her dad Corey — yes, walking! — and proud Pawpaw Simms snapped a picture for all this Twitter followers.

"Aliannah and her daddy," Corey's father Jeff wrote. "Each step she takes represents an answered prayer!"

Credit: Twitter

This is a big deal for Teen Mom 2 fans as we've watched little Ali struggle to keep up with her twin sister, Aleeah, thanks to a mysterious muscular disorder. But according to Leah's ex in-laws, Ali's doing better than ever now that she's been officially diagnosed.

"She is progressing," Jeff recently assured a fan on Twitter.

Leah and Corey have yet to reveal what's ailing Ali (we'll probably see that in Season 5, if Teen Mom 2 get renewed), but at least they finally have some answers and can proceed with treatment. Just last month, Leah posted a photo of Aliannah riding an exercise bike during a physical therapy session.

Can you believe how much progress she's made in the past couple years? Just thinking about it puts a smile on our faces. Be sure to leave your thoughts, prayers, and well wishes for little Ali in the comments below!