I'm trying to work out whether I am still sure that not being a mum is what I really want still. I'm concerned that I will live to regret it

My partner is older than me and I moved away from my family and friends to be with him. I have now become very aware that in later life I may face life alone, I have an elderly relative who regrets not having a child, despite remarrying she feels very lonely.
Anyone have regrets or perhaps at peace with such a decision ?