That's closer to Norwood 3. Good news is you have empty bald triangles at the side which tick the box for a transplant. Also thick hair elsewhere. Age is a little too young but shouldn't be a barrier as long as you are on meds.
Only the Doctor can tell you after examining you but I reckon 1500-2500 grafts. Depends where you draw the hairline, dense packing or not, thickness of your hair, donor reserves and if the forelock is reinforced. I don't think they will put much into that forelock currently.