Maggie, our Border Collie/Lab Mix, at 14 yrs old started tripping herself when running across front yard.
Then she started having difficulty getting up/down.
Within a months time she needed help getting up.
That quickly turned into not being able to squat to do her business.
Week later she would just fall down and lay there with that pitiful look of 'help me'
We made the decision to let her go...her quality of life was not good and it was painful for her when attempting to help her.
Hard decisions....but they have to be made.
It is part of caring for them.
Sorry to hear of Pegs' issues.
Best wishes.