Sorry I'm no expert.
From what I've read in the forum and elsewhere, exercise seems to affect BG differently in different people. In some cases it seems to temporarily increase rather than reduce BG levels.
As always, you probably need to use a meter to find out what happens to you.
Most "experts" seem to agree that in the longer term, exercise is beneficial.
In my case, I have upped my gym visits to three a week and increased my regime. I'm 57.
On Mon, Wed and Fri, I now do about 35 mins on the treadmill, walking for 3 minutes and jogging for 2 minutes and repeating. On Wed, I also do some weights, 5 machines, 9 sets each on varied but low weights. It's taken me a long time (years) to build up to this level.
I'm losing weight, my BP is down and I feel better for it.
Whatever you decide to do, take advice and don't jump in at the deep end. If you're using a gym, get some free advice from the instructors and build up slowly.