I would not confide in any JW about this. Even if they claim they won't hold anything you say against you, even your best friend is likely to tell the elders. They may do it because Jehovah is watching, or because it's for your own good in their eyes. Sometimes, they make promises like these without truly realizing that you might have something "apostate-like" to say. So they think they can keep the promise but can't.
I hate to say this, because I'm not big on the idea, but you could try fading. I didn't see if you were still living with your parents or not, but obviously if you are, that will be hard to do. :-(
I wrote a couple articles online about fading that offered tips on how to do it, but I'm sure there plenty of them available here, too. Note that my family aren't JWs (just my in-laws, who annoy me more than often than not) and even if my family were JWs, I've never been close to them. So it's easy for me to say you shouldn't fade. But maybe, in your case, you should consider it as an alternative to coming out.
Of course, everyone will eventually realize what has happened. But at least you won't officially be DFed for fading. The length of time required varies depending on how many witch hunters you have in your KH. It could be a matter of months.