There are several athletes that have started later. George Weah was 22 years old when he was signed to play professionally in Europe. Likewise Ian Wright was signed to play for Crystal Place just before he turned 22. Nate Quarry did not play any organized sports until he was 24 then was quickly drawn into MMA and made his debut at 29. Dikembe Mutombo did not begin playing competitive basketball until he was in university and ended up winning NBA All Star eight times. Javi Varas was not signed to play professional football until he was 23 and is now one of the top goalkeepers.
Do not give up.