It can take 7-8 years of consistency to reach your genetic potential;
Muscle gain is front loaded; most of it is gone in 24 months:
Year 1 -> 20 to 25 lbs
Year 2 -> 10 lbs
Year 3 -> 5 lbs
Year 4 -> 3 lbs
Year 5+ -> 1 to 2 lbs per year
Know that this is CONSISTENT training.