[Raro]

My advice is to take her to a store that has a good selection of helmets and start trying them on. That's what I did. I didn't look at the price or colour, just kept trying until I found the best fit. Everybody's head is a different shape so trying them on is the best way to go IMOP. I settled on a Arai Signet (now I think its called the Profile). My wife hated the full face helmet.

I also use the disposable ear plugs. After meeting a fellow rider at a gas station, who yelled at me because he was almost deaf from years of riding without plugs, I decided to wear them. Now I use them all the time.

Good Luck!