Is this silly of me?

I am still in the big old house with the huge garden.
DH died a year ago but I am not ready to leave yet.
I spoke to another widow recently who said she waited 5 years before selling and she has just moved into a bungalow on a bus route
She's in her 80s but still fit.

I would miss the garden too. It is mainly the prospect of increasing costs which frighten me and may drive me out eventually.

You sound in a similar situation to me, a couple of years ago. We had lived in the same house for 33 years, huge garden. At 65, we started to talk about downsizing, as the spare bedrooms were only being used a couple of times a year when adult offspring came to visit. Then my husband died suddenly, and I was forced to sell up, as I became nervous in the house on my own and couldn't deal with the garden by myself. When it came to moving, yes, I was sad, it was very difficult to dismantle 33 years of what had been a very happy family home. But, when prospective buyers came to view, and I saw the excitement on their younger faces as they realised the potential of the property, I was happy to hand over the keys to someone who would get full use of the house, with every room being filled with love and laughter.

It's hard to leave a home with emotional ties attached after so many years. If you can see it as life's chapters it makes things easier. I grew up in a large house in London which my mother then gifted us as a wedding present, our young children grew up there. So many memories when I finally closed the door and drove away to pastures new. But things move on and it was the right decision. Since then I have moved at least 10 times!
I'm sure you will work it through.

It isn’t childish at all. You love your home. I expect you would love a new one just as much especially as the garden worry would disappear.
There are two types of people - those who find this sort of thing difficult and those who live change and take the ‘it’s only bricks and mortar’ line.
It’s usually the memories a home represents rather than the building itself. And you always take those with you!