L.,
I moved all three of my children in to a toddler bed at 14, 16 and 17 months respectively. Each was different, and not all of them were climbing out of the crib at the time. The first was and needed to be moved out for her own safety. The second was big enough to, but hadn't yet and started a change in sleep patterns like yours, and the third, well he was so easy to put to sleep that we decided to give it a shot and he did great. We did use a gate at the door for all three for our own piece of mind and their safety as well. And I continued to nurse all of them well past the change in beds.
Depending on where your room is in relation to your son's it sounds like it might be worth a try. I would definitely recommend a toddler bed. They're low to the ground, you can use the same mattress from the crib and they have built in side rails. They're not perfect and I have had a child or two roll off onto the floor, but we were only a room away to wipe away the tear and put them right back to bed. If it doesn't work, you can always go back to the crib at least for a little while longer, but from the sounds of it, it sounds like he's ready for a change.
There is NO right or wrong age for the switch. Just go with what you feel comfortable with for his safety and well being as well as your own.
Blessings,
Rolinda