A picture book from the 1980s, potentially from the 1970s, about a little boy who wishes to be older. His neighbor grants his wish (with her magical garden I believe) but he decides to go back when his mother doesn’t recognize him. I believe the illustrations are in a style similar to Ron Barrett.
Stump the Bookseller
New format, same book stumper solving.
Might be Barney Bipple’s Magic Dandelions
by Carol Chapman, illustrated by Steven Kellogg.
That’s it!