These comments that have been made are straight to the mark:   heed them well ...

1. It has probably already been done.   Thousands of times.   Go find it.
2. Most “simple” requirements grow, quickly, into a “true” statement of the actual business need ... at which point you find out that you really did need the “bigger” tool, and that the aforesaid tool already exists.   (See #1.)
3. It makes not one whit of difference “how fast” the tool runs.   What matters is how rapidly and how accurately you can get the job done ... by findng the already-existing tool, selling your management on the idea, and getting it in place.
4. It is much too premature to assert that “you will use XML to store and retrieve data.”   At this point I seriously doubt that you know that there is a business requirement for such a project parameter.

While it might be “a fun and informative exercise” to use this opportunity to bone-up either on your PHP or your Perl skills, it is unlikely that this is the right time or place...

Unless, of course, your company has given you this project as a throw-away learning task, and e.g. they have specified the use of XML and so-on, given the choice of PHP or Perl, and so-on.   In which case you are effectively “taking a test,” and you want to show that you are very thorough, doing your research first.