In this dream I'm in a place where soldiers are. At first I see soldiers getting military haircuts. I think I also get one too. I'm with my mother both of us go talk to one of the soldiers. My mom I think asks if I could join. I felt hesitant in joining thinking that I wasn't good enough for this. So I left.
Haircuts can mean many things depending on how you FEEL about the haircut, or haircuts in general.
To me it sounds like you want to "straighten up" your look, and image to those around you. Military haircuts usually show people that you "have your **** together", and its usually just an assumption without really knowing the person. You wanting a military cut would make me think you want the world to see you like that.
You thinking that you aren't good enough would hint towards that you feel like you are "too messed up to staighten up". You know your "hair" isn't the problem though. You feel like you would be tricking people, and that they will think you are more put together than you really are. Which in turn makes you feel unworthy of the haircut.
If I were you I would start thinking about things that you are trying to seem like you've got control of, but you don't feel you are worthy of.
Haircuts can mean a change in identity; here, it is a warrior - standing up for yourself more. it oculd also mean you may consider a career in the military.