Administrator? I am giving myself 8 months to learn it. What is the platform who will give me the best chances to get into that field without experience? Oracle or SQL Server? I am planning to set a lab to practice. I am 48 years old with no IT background.

Ive been in IT for 10 years, healthcare field - all sql server. only 1 client out of over 200 used Oracle. And they eventually dumped it to coordinate with what we worked better with: sql server. You may get different opinions but that is mine from experience in the Software development field for the Healthcare industry.

EDIT:
Found this article which may answer your question:
http://databases.about.com/library/weekly/aa060401a.htm