Sorry, we are not going to engage in discussing what seems to be a very risky behavior.
I caution the OP, that continued posts on how an underage person can get a gun or parade around with one - even if legal - doesn't seem to convey the correct attitude.
Find a program for young shooters and/or hunters. Get parental consent and follow the laws and common sense.
If an 18 year old walked down the street with a MP5 that is full auto, expect to be at the end of the local SWAT team and with good reason (spare me the RKBA rationalizations).
Become of age and get a concealed carry permit or license. Also, take the appropriate courses.