As a 21-year-old, you should spend more time studying/reading than playing. Kids play lots of rapid and blitz games to get them motivated. However, you don’t learn very much from playing speed games against other beginners. So, study chess principles—openings, endings, middle game planning. As a motivated adult, you should be able to learn quickly and then be able to apply your learning in games.
several suggestions:
1. Analyze your losses. Don’t simply look at the game review, since that only shows individual moves and does not explain long-term plans.
2. Don’t try to memorize long opening sequences. Stick to general opening principles.
3. Play rapid or classical rather than blitz. Give yourself time to think.
4. Learn basic endgames. King and pawn endings. The principle of opposition. The strength of outside passed pawns. Rook activity.
as an adult, you can study and learn efficiently, so you will advance more rapidly than kids who are learning by trial and error from only playing blitz games.
Well, I am new to chess but I read it on medium that it requires a person atleast 5-6 months to achieve these ratings,but personally I think it depends from person to person.
What do you guys think?.