Absolutely not. The average gamer age is 35 years old (ESA 2023). 26 is squarely in the core demographic.
Only if it displaces responsibilities (work, relationships, health, sleep, finances) — same as any hobby (gambling, alcohol, social media, TV). The issue is compulsion, not the medium.
Enjoy your hobby. Ignore outdated stigma. Many 26-year-olds are building careers, families, and hitting Grandmaster in Overwatch.