My husband and my grandson both got taller after 20. My husband was 6' 8" when I married him at age 22. I don't think he got taller after 22. My grandson is 21 and at least an inch taller since I saw him last. He's 6' 5" the last I knew.
I can tell you to stand straight to avoid losing the height you have. Forty years later my husband has shrunk 4". It could be aging I suppose, but he has done a lot of slouching over the years.
I guess you could wear higher heels. Height mostly is inherited I think. If you got tall family members you can expect to grow taller as well, but you may not get that gene. My son is 6'2", not quite as tall as his dad. It skipped over him.