You are completely normal and healthy.
If you look up "Circadian Rhythm" on Google or Wikipedia you'll see that your readings are precisely what should happen. They vary cyclically over the 24 hr. period, being minimum in the morning, maximum late afternoon and evening.
The range you say is not only excellent for a 55 yrs old, but rather better than most, so ceasing being vegan has clearly benefitted you. Most people's top reading is (as a rule-of-thumb) "100 + your age" so you have no worries.
Take no notice of all the numpties writing here on Answers about "slightly elevated" or "a bit high", as they are quoting bits from Readers' Digest, High School chemistry, nursing courses, and the like....
- NOBODY'S BP's stay the same, and in any case, the readings aren't actually real... That is, the pressure in your artery
isn't what the monitor reads,... just think about it, . Why should it be?
I'll offer £1000 as a prize to anyone who can convince a panel from the Royal Institute of Physicists that the pressure a Riva cuff indicates is an accurate measure of the intra-arterial pressure, with a theoretical explanation of why it should be