Help me feel better to be one and done

I have a toddler daughter and i am at the point to either have another or not. I am an only.

For the most part i really envisioned being oad but i have been swaying because of her in her later years. I watched my grandparents have good connections with their siblings and clarified for me how really alone you will be in the later years. This has colored family and siblings different for me. Most of the time i would see dysfunctional sibling relationship and i am glad to be an only and i have a wonderful husband.

I had a great aunt whose daughter was in worse medical shape then her and relied on her brother(my grandpa) for help at the end of her life.

I guess im struggling because i see positives with a little bigger family. At the same time i am uniquely equipped to help my daughter to have a happy only childhood that imagined for her. Yet i would feel insanely guilty to have her have to compromise time/ her room/ parents with someone else.

Also i guess i like the idea of siblings helping each other when their love life may not be working out. Lets face it a lot of people struggle with relationships. My husband has a good sibling relationship big family and they give me hope, with lots of siblings and no drama.

Just would like to hear peoples thoughts. Thanks!