The higher reading, the Systolic pressure, varies enormously with one's exercise,emotional state, thoughts, digestive state, hormonal status, etc.
The lower reading, the Diastolic pressure, represents the true B/P when the heart is resting. Anything between 70 and 90 is relatively normal.
135/91 is marginally OK for a youngish person. Quit worrying about it, or your Systolic pressure will go haywire.
So, at her age, the diastolic is a tad to high, the systolic marginal..........I can understand why you say you have seen worse. My mater (78) was, at one point, 170/105 and her last one at 105/62 (one time she was 48 on the diastolic - and we joked that she was dead - the doc readjusted the bp medication - her cataract surgeon was delighted as, apparently, the surgery favours those with low bp - I have no idea why.
I am 68 and I take co aproval 150mg/12,5mg. The thing is last week couldn't get to the docs to get my health card recharged with meds, (sqad will understand that) and was ekeing them out and skipping a few days, but it will be OK now won't it, I'm usually 120/70 (I think)