If you apply for Jobseekers Allowance (or Supplementary Welfare Allowance while your claim is being processed), your parents means will be taken into account under Benefit & Privelege, until you are 25, after which you would be assessed only on your own means. See following for details http://www.welfare.ie/EN/OperationalGuidelines/Pages/ua_benpriv.aspx
In addition to the Benefit and Priviledge assessment mentioned above, there is also an age-related reduced rate of Jobseeker's Allowance payment for persons under 25.
The maximum rate for a person aged 22, 23 or 24 is currently €144pw