He could be 15 by the end of the season, most likely 13 or 14.
That's 15 in 2028 assuming next year he tries the triple GT and doesnt win any. If he remains motivated, could be 17 in 2029 and eventually 19 in 2030.
This year one more GT, next year 2 more (at least) so 8 total.
9 in 2028, 10 in...