Don't put mental hurdles in front of yourself. 55 may actually physically (or policy-wise) be too old to do certain jobs like for example, joining Army Special Forces. However, programming is much different and it can be done pretty much until you have passed away as long as you have working hands and a functional brain. Just remember to be patient with yourself. The answer is, can you still learn anything? Do you find yourself learning every? If so, you could still learn to program!