Any competant adult can handload ammunition safely. Adult, by the way, is not an age, it is an attitude. If you can read and comprehend, and are detail oriented, you wil do fine. It is an advantage to have an experienced coach help you get started, but it is not absolutely neccessary.
My advice to you is to invest in a couple of books.
I recommend the Lyman realoading manual, and Richard Lee's Modern Reloading. Both are excellant resources, filled with a lot of valuble information about handloading. Chapters on primers, cases, bullets, powder, etc.