That's fine as long as there's no one to wake up in the morning and find you before you're past the point of no return. I think most people do it at night because everyone they live with is asleep and they have several hours before anyone would find them. I believe you need a minimum of six hours to be certain that you won't be saved. Don't quote me on the six hours thing because I'm not completely sure. I'm not quite as worried about the time aspect as some people need to be because I live alone.
If only there was a magic pill that you swallowed and instantly died like they have in the movies.
I suppose, as long as you're not writhing around or making any noise, they might just think you're sleeping and leave you alone.
On the other hand, because it's morning, they might try to wake you up and discover what's going on.