You can say just that - "I am a social person." OR "I'm good socially." Sometime we also say "I am a people person."

I am no wall-flower.

"I'm a sociable person." or "I'm a very extroverted person." (from Jungian theory), or simply "I really like people." or "I'm a people person." Those are some ways.

friendly

How about: "I'm really outgoing!"