Hi there,
I'm sorry noone replied to you so I had to.
Anyways, not a bad song you chose, first off. I kinda liked it. It's at least a lot better than some song about someone's private parts or a rick roll with a cringe voice (Seriously, I've seen that stuff in the WIP section. I have no idea what they're thinking and how that stuff is going to get ranked.)
So I don't map out osu! mania; I map out the standard mode. However, I took the extra step in testing out your song in both the osu! page and in the editor and found out that maybe you actually don't need a preview time. I mean preview times are for much larger periods of time where a person has to wait for a song to show its map to you otherwise and they want to skip it because, of course, they want to play the darn level already.
On the other hand, in your level, noone has to wait too long to start playing your level, so I think you don't even need a preview time. Furthermore, according to the mapset verifier program I downloaded, which is like the aimod, but far better (thank Naxess for that!), preview time usually lasts 10 seconds. You put a preview time in the middle of the song for some reason, which doesn't make sense, because why would there be a skip button in the middle of the song? You get what I'm saying?
In conclusion, I really don't think you need a preview time. Adding one in fact will actually catch a good number of people off guard because it's skipping only a very short portion of the song and they don't have enough time to prepare to play the map you made consequently. Think about it, would you need to skip only like 2 seconds of the song just to start playing its map? See what I'm saying? So just delete the preview time because I think you don't need it and it's making things harder for you.
If you don't believe me, check with a person mod AND download the Mapset Verifier yourself from the Osu! website, even though the person mods take time, but it's better than wildly guessing right now.