Hi icy,
For the record, even seeing only lower half of your face, you don't look old. Your tooth display is less than average but that is one of numerous factors that make people look prematurely aged. Your recessed jaws/chin is actually quite youthful even with the convex profile. Usually it's the opposite that leads to the aged look... a concave profile, loss lip vermilion, excessively prominent chin, etc.
With that said, yes bi-max is what you'll most likely need and I while your case is seemingly borderline, it probably isn't. Surgery should resolve your functional and aesthetic issues if properly executed. My case was "borderline" too and I was a kind of unusual class II as well. A previous round of braces masked my overjet by retracting my upper incisors. Except I had vertical maxillary excess aka long face syndrome. But if I could have avoid jaw surgery with orthodontics alone, you bet I would.
You'll most likely require clockwise rotation of your occlusal plane via inferior/forward movement of your maxilla to sufficiently expose your upper teeth at smile and rest. Your nose seems to naturally tip upward a bit so it's contributing to the obtuse angle. Yet your maxillary sulcus contour (upper lip curve) looks normal. Not flat despite the obtuseness. Still, your nasiolabial angle should improve after.
Then of course mandibular advancement to correct the lower jaw deficiency and give you a class I bite.
In regards to the possibility of a witch chin after surgery, unlikely unless the movement's are done incorrectly. When you have clockwise rotation with upper/lower advancement. Part of the forward movement is re-directed downward so it offset's part of the horizontal advancement. And your mental-labial fold should improve (area between bottom of lower lip and chin pad) as it's a bit deep right now which is typical class II's. With the lower jaw coming forward, it'll actually straight the fold so it's less acute.
Hope some of my input helps.
