So, is it an anxious worry then if you aren't sure what her blood pressure is? I personally have high blood pressure. I take medication which lowered it almost immediately. But you have to know the numbers (and not from one reading) to know if it is hypertension or pre hypertension or normal. A blood pressure cuff at home, taking bp two or three times a day over a month or two really gives a pretty accurate picture. Maybe you could purchase one of those for her and ask her to track it?
Hypertension is something that can bring death on sooner but is more of a chronic disease. It does damage over time. What is your mother's blood pressure?