I asked is it ok if map starting 30sec late and then end 30sec before the song ended. Ya, I do got a reply. And a mocking word towards me too. It like cursing much on new mappers asking questions. Behave yourself
I am not sure if this is a rant or an actual question...
Generally it is not recommended to start the song late and end the song early because of the filesize and the fact that there are lossless cutters such as viewtopic.php?f=56&t=34303. Still, there are scenarios where they are appropriate such as a song that goes with a video (can't think of any other scenario right now)
As for your experience on #modhelp, I'm sorry to hear that happened, but I don't think there is much I can do to help.
Don't take it too personally (I was actually watching chat when that happened)
There are just some people in chat that are harsher than others, they aren't trying to be mean that is just how their personality is. Most of the time #modhelp is "fairly" friendly so don't give up on it for advice.
(As mentioned it is fine to have a space at the beginning/end of your map if there is a good reason for it)