Just one more vote in support of pellicle's advice...
and I'm a real world example of what Chuck C mentioned.
I was diagnosed at 10 with BAV and no stenosis...However the cardiologist gave a graphic description of aortic dissection to my mother and there was no turning back and no way a second opinion was going to unring that bell. She convinced my mom that just about any competitive sport would be life threatening...
Once I was an adult, and moved on to other cardiologists, they all said the same thing: no restrictions and the worst thing anyone could have done was try to restrict me from competitive sport and any activities at all..oops.
My stenosis crossed over from mild to moderate in my 30's (with no restriction on my activities).
In my late 40s it went into the moderate/severe zone and I stopped doing anything that wildly increases blood pressure (dead lifts for max weight, weighted pull-ups etc.).
And the last few years it has been severe but I haven't had any symptoms or restrictions until a couple months ago...As a percentage, my valve narrowed more in 5 months between April and September than it had in the last 15 years...
Now ill be heading into surgery sometime in the next few weeks...the only 'symptom' i ever noticed was 'exercise intolerance' that wasn't really intolerance, it was really just a lack of certain sorts of improvement in fitness given the amount of exercise I was doing....That said, I imagine it is entirely possible that after surgery I might say, "Oh wow, I didn't realize how much more tired I was or how terrible I was sleeping etc".
The moral of the story: There is literally no reliable way to tell how it will progress. And it certainly isn't linear. You may make it to 75 or it may get worse quickly. Find a cardiologist you trust...Get a regular echo...live your life...and maybe give up on dreams of breaking the world record in the deadlift.
Hope that self-indulgent ramble was of some use
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