Can I Concealed Carry and purchase a handgun at 18?

Question

In my state of Montana at 18 I can apply for a Conceal Carry Permit, does this mean i can carry a handgun? Is it legal for me to buy a handgun from a private party? Ive heard many answers from many people but my vague understanding is that as long as the gun is bough from a private party its legal, it seems like the 21 age is just for licensed FFL's.