First, let me welcome you to the site. You've found what we believe to be the best place on the web to learn about heart valve surgery - from the patient perspective. Second, let me be very clear - I am not a doctor. I'm just another patient who has had a valve replaced (and some other miscellaneous repairs along the way).
That said, I would suspect that yes, surgery probably is in your relatively near future, but maybe not all that near. The medical profession has statistical criteria as "triggers" for intervention for each of your conditions. For the stenosis, aside from watching you for symptoms, I think they tend to recommend surgery when the valve area becomes less than 1.0 or 0.8 cm2. You have some time there. With aortic aneurysms, IIRC, the action point is when they hit 5.0 cm (I could be out of date on this one). Again, you have some time. The sticky one is that LAD blockage. I am surprised they did not recommend immediate implant of a stent to open that artery while you were in the cath lab. That would be worth asking your cardio about.
In my case, we found out that my LAD was about 50% blocked when I had the cath in prep for my valve replacement surgery. My surgeon told the cardio at the cath lab not to stent, though, as he would just do a bypass "while he was in there." If they are expecting you to have valve surgery soon, that may be why no action was taken on the blockage. I would move this blockage up in your priorities. A 90% blockage of the LAD can be serious (Google "widow-maker"), while your other co-existing conditions may be less volatile.
I imagine some others will be along soon to join in, but whatever you do, take a deep breath. Maybe tell us where you're located - somebody may have some recommendations for doctors, surgeons or hospitals nearby. They will probably also know more about the combination of conditions than I. Hang around a while, and keep asking questions. That's why we're here.