Hi NaR I think as a New Member, you can only edit a post during the first 30 mins.
In an attempt to prevent certain abuses of our site, new members have a handful of minor restrictions placed upon them until they have made 10 forum posts (gallery comments do not count) AND have been a member of the site for 5 days. The following minor restrictions apply to new members who have not qualified with the above criteria:
Creating a Signature, Uploading an Avatar, Creating a Blog, Editing their posts after 30 minutes, Editing the Opus, Creating a 'For Sale' thread and Voting in polls.
The time will soon pass, I'm sure.