My handwriting is shocking, it always has been.
Back in the 90's I was even allowed to use a laptop in school exams and national exams because it was that bad. The faster I try write something down the worse it gets, if I can take my time then it readable and OK, still looks like a young childs handwriting mind you. However if I have to write fast (e.g. taking notes, writing an exam or the likes) it goes down hill verrrrry quickly.
It's just embarrassing as a 26 year old to have the hand writing ability of a 8 year old its very annoying and would love to actually go back and learn to write properly but I suspect even with professional "lessons" it wouldn't do much good, I did have help with it when I was a lot younger to no avail.
Throughout university I took notes via hand instead of a laptop, and I use to have issues reading my own handwriting. Quite annoying!