I'm so sorry about your cat, Sofia. It's always so very hard to lose a beloved pet. It has happened to me several times.
I do think the ashes will be comforting. We have the ashes of our last dog, Rusty, in a beautiful little chest that I picked out especially for him. It's in our study on the shelf and makes me smile when I look at it as I remember my time with him.
I know it's hard to believe now, but you will feel better in time. When you're ready a new pet will help a lot. We adopted another Golden and it has really helped heal our broken hearts.