America didn't enter WWI until 1917 / 1918, and so if your grandmother was born in 1910 and married someone just a little older, the ages would fit.
Or he could have lied about his age, as many did.
You should be able to tell his division by looking on his shoulder, here is a page that shows what they look like:
http://freepages.military.rootsweb.ancestry.com/~worldwarone/WWI/insignia/shoulder.html
Suspect that the crossed rifles just mean infantry, and that 19 is the battalion, but someone who knows uniforms of that period may know more.
Caregiver may know he is a fund of Knowledge about the wars , the braid maybe he was an officer, they called it scambled agg, crossed rifles may mean Infantry the 19 may be the regiment number, but I really dont have much info on WW1 although my Grandad died in that war.