The actual limit for renewal is 155/95, so you are nowhere near that. Also the 140/90 that you talk about is uncontrolled.
If you average 3 readings were above this then they would likely give you a 24 hour pressure cuff to wear so that a more accurate 'average' could be taken.
If this was also shown to have your average pressure above 140/90 then they would likely advise that you visit your GP and try some 'medication', after a few weeks you would then have another reading to see if your pressure has reduced.
Its a funny thing BP, you may suspect it is high so that stresses you out during the medical which can lead to even higher readings. From the sounds of you their isn't any significant lifestyle issues so I doubt you will have any trouble at all. Also you can't rely on those 'at home' machines unless they are calibrated and verified by your GP.
I know lots of guys and girls flying in the airlines with high BP that is very successfully controlled through lifestyle/medication and it doesn't stop them holding a class one.