Aparently girls can tell if a guy is a loser or to immature for them?

can a girl tell if a guy is to immature or like a loser or whatever or not for them or their type? i was out me and my friend met up with this group of 4 girls well i like one her name is krista we sort of know each other from school, my friend msotly talked to her since i get shy talking to girls and sort of freeze up but i talked to her a bit and we talked a bit for like 5mins i even tryed to look witty crakcing some jokes in the group. anyways i asked my friend who knows her well if she likes me or said anything about it and she said that another girl said i was undateable since im to immature and act like a loser and the girl i like agreed to it she said and said well hes cute but he acts like my little brother and dresses young and seems like a loser but i dont get why she would say it? can you tell me some signs of things i might have done please girls? like how can a guy act overly immature and be to shy maybe? or how can you spot or tell if a guys a loser what are some signs and stuff? thanks for telling me some stuff if you know!