I'm a knitter, and my mom is a long-time crocheter. She really wanted to learn how to knit though, but she was born with only 3 flanges on her right hand (thumb and two fingers) so holding and maneuvering a knitting needle was very difficult.
Then, she found the Knook, which is a crochet hook with a tapered end, with a hole in which to run a ribbon. The ribbon holds the live stitches while the hook makes it easier to knit.
That might work for you if you find holding two knitting needles difficult?