Your Mom is clearly a very different person to who you are, she has travelled a different path to you, had different experiences, she has probably expected different things from society, she has perhaps felt it necessary to conform, without even knowing that is what she is doing, she is from a different generation, a different upbringing. I am of course guessing these details. If I can assume she is different from who you are. Why do you expect she could understand the experiences you and alot of others receive on the dreadlock journey? It is very hard to tell some one of an experience and have them understand fully. Tell her you are happy, even better show her you are happy, that is all a parent really wants.
I did have a similar experience with my Ma, I was dreadlocked, going to India for retreats etc, travelling all the time, I was happy, and when I came home to visit I was beaming, I could not get the smile off my face, I would tell of my experiences, and we had a great time, but she could not have really understood what I was feeling, but I was happy, it is surely hard to argue with some ones lifestyle if it suits them. If you are happy and you can show that on your face, there is not much more to tell. Live it, be happy, your Mom can't argue with that, she is probably trying to understand, but without your experiences, which is what has allowed you to understand, it will be much harder for her to get it. Take care, love what you are doing and others will 'get it' in there own way.
Just my opinion, I understand I do not know you or your Mum, I'm not trying to be a 'know it all', just my thoughts,