Is there any reason why a violin student (64 yrs old) can’t modify a bow hold and bowing to suit the way her aging body can do it in a way that suits her needs or desires?

My finger, wrist, and arm joints are not that flexible. I want to learn the violin. I am not going to play with anyone. This is just for my own benefit and enjoyment. I have been on other forums and they are loaded with classical violinists and any response will be that you have to do it the way classics do it. All I ask is that you please do not go down that road with replies. 

Here is the issue. I have issues with my joints, just age, not specific medical or physical issues.

I have an issue with bowing the way classical violinists bow. I have always used bulky pens, bulky knitting needles, etc., never anything thin like a violin bow and this is causing me issues that I did not have with the fatter and heavier cello bow.

I do play cello, although, still learning. The cello bow and weight is much easier for me to handle. The violin bow is so lightweight and skinny that it just does not register that it is in my hand, especially with the “wimpy” way it is held. I don’t know how else to describe it. 

The thumb is extremely uncomfortable. Nothing helps. All those little exercises have made things worse because I am being forced to do something that, in my 64 years, I have never done with my fingers. I have never held skinny objects or at least, if skinny, held with light grip. 

For me, that thumb position notch at the frog on a violin bow is just not big enough and not going to work. If I can hold it so I can feel it, couldn’t I adjust everything else? I am not going to play solo in front of anyone, I am not joining an orchestra. I do not even have dreams of playing classical music. What is wrong with someone who has no professional goals, is dealing with aging joints, etc learning to do something in the most comfortable way for that person and adjust things as needed as she moves along?

I understand that this could hinder extensive complicated classical pieces, which I have no desire to play. I want to be able to get a violin book of songs, melodies, (Danny Boy, English Country Gardens, Moon River, etc, not Allegros, etc), etc and be able to play them to the best of my abilities, for myself and my own self worth. I have no aspirations to be playing fast allegros or anything like that. I just want to have relaxing enjoyment. I am not going to perform in front of anyone.

Is it possible to do this? I started using my viola bow on my violin. It is heavier, which I love, and a little more, just a little more, bulk in my hand. It works much better for me than my lightweight carbon violin bow or my lightweight wood bow. But, it is still not registering as I get into the melody. If I adjust my grip to what I need, it won’t be traditional violin hold and it will be pointed out in my lesson, but it will work better for me.

Is there any reason a violin instructor needs to force a student of any age, who is learning the violin solely for his or her own enjoyment, to be hindered by the crazy classical violin hold if that hold just does not work for that student?