Perfect beginner dirt bike for a lady?

I ride dirt and street and want to get my wife something she can learn on as a brand new rider with zero experience. I started on dirt and I think she should too. She's 5'9, 140lbs. I plan to start her out on flat open spaces, teach her the basics and then let her skills grow naturally over the weekends until we can explore some mellow Colorado mountain trails where, God willing, the views will cause her to fall in love with the sport.

Any input is appreciated!