Hi.. My son is 3 1/2. He started to climb out at about the same time as your child. I had left the side down so he could climb out but it left a small barrier so he couldnt roll out in the middle of the night. When I felt he was ok with that. I moved to a regular bed no guard rail at about 24 months. We put down soft comforters on the floor for the first week or so just in case. He fell out once, cried a very little bit, then got back in bed and never did it again.
I decided against going into a toddler bed that is low to the ground and uses the crib mattress because my son is very tall for his age and already seemed fairly cramped in the crib at 2.
Most children can go use a toddler bed till they are about 3 years old max. They can stay sometimes stay in them till they are 4 if they are small, but ya don't get a whole lot of use out of them. A year goes pretty fast.
My neice bought a toddler bed for her daughter and she never got more than a years use out of it, and her daughter is small for her age.
If you have already taken the side off the crib completely and they dont roll out. Then I would say they are ready to go into a big bed. A crib mattress is at least as high off the ground as a regular mattress and much smaller and easier to roll out of.
Once they can sense their boundaries, which happened pretty fast for my son, they usually have no problems in a big bed.
I was a baby furnature salesperson for about 7 years before I became a mom. We were told that any time after a year old, once they climb out, it's time for them to leave the crib. Whether you think a year or so of use from a toddler bed is worth the expense is up to you.
I hope that helps.