Hi, hon.

There's only a certain amount of time you have to edit and I believe that is four hours (don't quote me on that though).

When that time is up, the edit option won't be available and you have to PM a moderator of that forum, or an administrator.

You could also report your first post in a thread by choosing the "report post" icon, and explain that it's your thread and you'd like it deleted, edited, etc. The report will go to every mod in the forum and all three admins, so someone will get to it quickly.

That hopefully answers your confusion about not always having the option to edit.

Don't hesitate to ask if you need...

Have a great night!

KD