No Basel,there is no method of working out what one's BP SHOULD be. Each person is an individual with their own personal problems, past and family history and underlying medical problems,
That is why I HATE websites and links on the health section of AB. I never open a link and will never if at all possible,give one.Medicine is all about people NOT cyberspace.
Getting to your OP and the medical details that you have given and those that I have gleaned over the year's on AB,your cardiovascular seems to me to be in moderately good nick,although your BP is a touch above normal.
My advice would be to soldier on taking your BP weekly as at the moment it is not a big deal.
However,if your GP,feels that a low dose of BP lowering drugs may be appropriate then I would also consider that to be quite appropriate and acceptable.