You need to take a one-turn penalty for infringing <&= rule_link('31') &>.

RRS 31 & 44.1 are the rules you need to look at:
The "starting pin" is a mark of the course that (from RRS 31) "begins... the leg of the course on which she is sailing"

And from RRS 44.1, "She may take a One-Turn Penalty when she may have broken rule 31."

Unless the NoR or Sailing Instructions specify a different penalty.

Thank you very much to all of you answerers,
 my doubt has been perfectly cleared.

Only other comment is that a boat must get well clear of other boats -- as stated in 44.2 -- before taking a penalty.

Did you touch the course side of the starting pin?
Nothing else is within the racing area.

Phil,

Can you just show us some rules, references and argument that supports your assertion?

It seems to be inconsistent with the definitions of

Racing A boat is racing from her preparatory signal until she finishes
and clears the finishing line and marks or retires, or until the race
committee signals a general recall, postponement or abandonment.

and

Start A boat starts when, her hull having been entirely on the pre-start 
side of the starting line at or after her starting signal, and having 
complied with rule 30.1 if it applies, any part of her hull crosses the 
starting line from the pre-start side to the course side.

PHILIP asks:
Did you touch the course side of the starting pin?

Answer: YES, I crossed the starting line with the bow, but I was too much close hauled and slowly I touched the pin at half of the hull.  

You left out the beginning of RRS 31: While racing, a boat shall not touch a starting mark before starting, a mark that begins, ........

A boat can touch a starting mark and cross the starting line (Yellow), or touch a starting mark on the wrong side and not cross the starting line (Blue). See the two diagrams below.

Yellow's hull crosses the starting line from the pre-start side to the course side and touched the starting mark. Yellow took an applicable penalty for her breach of rule 31 by taking a One-Turn Penalty. She should be scored in her finishing position.

Blue's hull passed the wrong side of the starting mark and touched the starting mark. Blue took an applicable penalty for her breach of rule 31 by taking a One-Turn Penalty. Blue needs to start by crossing the starting line. If Blue does not cross the starting line from the pre-start side to the course side she should be scored Did Not Start (DNS).

You might find it useful to read Case 28 and Case 108.

Philip Hubbell

Said Created: Sun 18:28

I'm not sure why you think whether or not it's in the racing area is relevant, but we had quite an extensive discussion about the meaning of 'racing area' in this thread

At a regatta with multiple course areas boats having finished racing on one course cross another course.

Blue not starting correctly is a different issue, nothing to do with penalties for touching the mark.