Don't be hard on yourself for not starting sooner. Be proud of yourself for starting now.
The other day I was slicing up a bell pepper to use in a recipe, and then my daughter came and took a slice and ate it. My initial thoughts were:
"I don't know why I never thought to give her sliced veggies as snacks."
"I don't know why I don't do it myself."
In the past, my immediate reaction to these thoughts would have been:
feel ashamed for not starting earlier,
try and change my habits immediately,
go all in and burn out,
go back to my old habits.
An example of this was when I would try to exercise more. I would come up with a ridiculous expectation for myself: "ride my peloton every day", "go to the gym three times each week", "wake up early and run every day" etc.
Every time I would fail to meet my expectations, and then feel more shame because I failed.
Now I sit with these feelings and think to myself "I'm proud of myself for having this thought, next time I go to the store I'll buy an extra vegetable to have as a snack. I will look back a year from now and be thankful."
This small mental shift has led me to building so many habits over the past year. The progress is slow and many days there is no progress, but when I look at my journal entries from a year ago, it's blatantly obvious how far I've come.