Is there any software to easy manage data (Create, Update, Delete)
from a XML file?
For simple things, just loading the document into a DOM tree and
manipulating that may be easiest for a beginner.
If you insist on thinking about it as a database, though, you may want
something more like an XML database. If so I'd suggest looking at the
PureXML features built into IBM's DB2, but I'm biased.