There are legally defined children who have been through more, been responsible and held accountable for, and have been more productive and mature than adults.
There are adults who have no worldly experience, never grew up, and are untrustworthy and immature.
Yet, in this day and age we feel very obligated to define whatever comes across our paths to save time. Kids are considered immature and incompetent, useless and burdening. Adults are supposed to be the trustworthy and productive human beings, however this is often not the case. We're just too busy/lazy (can't decide which) to look at people as individuals rather than how long it's been since they popped out of the cooch.
Simply put, some kids are adults and some adults are still kids.
It depends on the way you look at it, and how long we've all been in this world.
Centuries ago, you were an adult as soon as you seemed big enough to join the military or until you sprouted boobs, so a nobleman could marry you. Each culture has it's own ideas regarding maturity, our current society happens to put an age limit on everything in order to define every person and our capabilities. That is likely to change within a few more centuries as well; we are evolving as people mentally, socially, and biologically.
Physically, on a typical scale, you're as good as any adult. Every other species gains reproductive ability and BAM, they're out there.
Mentally, I don't know you and I don't know your reputation and abilities. So, I can't make that judgment.