Losing salvation?

   Hi! Sorry I have posted in a while. This subject has been something I have wanted to blog about for quite a while, but I was waiting to come to a conclusion of which side I believe before I posted. Unfortunately that didn't happen. And I will explain why.
   Ok so the question is: can a true believer lose his/her salvation? Most people would say no. I say there are many verses that support both sides. You can't brush aside 20+ verses because you disagree with what they say.
   My church is a firm believer of once saved always saved. My parents however believe there are verses to back up both sides, and they will often lean towards the losing salvation side. That leaves me in the middle. I was leaning towards losing salvation is possible, but I decided to ask my youth pastor to explain to me how a couple verses that seem to say we can lose our salvation don't really say that.
   So my youth pastor explained Hebrew 6:4-6 to me, and I saw his point of view. Then I came home, and my dad disproved it. So now I'm going to show you what the two sides are with Hebrews 6:4-6.

It is impossible for those who have once been enlightened, who have tasted the heavenly gift, who have shared in the Holy Spirit, who have tasted the goodness of the word of God and the powers of the coming age, if they fall away, to be brought back to repentance, because to their loss they are crucifying the Son of God all over again and subjecting him to public disgrace.

   I'll start at the beginning.
"It is impossible for those who have once been enlightened,"
My dad would say that means they were a true Christian because only true believers are enlightened. My youth pastor says it is someone who was enlightened to the gospel.

"Who have tasted the heavenly gift, who have shared in the holy spirit,"
My dad would say only a true believer can taste in the heavenly gift or share in the holy spirit.
My youth pastor would say it is referring to someone who has been around believers a lot, maybe been to church a lot, and has experienced the Holy Spirit.

"Who have tasted the goodness word of God and the powers of the coming age"
My dad says tasted means they have consumed it, and only a believer can do that.
My youth pastor says that tasted here means tasted as in tasting wine. So it is talking about someone who comes really close to becoming a christian, but then doesn't. Like someone who takes a sip of wine, tastes it, then spits it out.
My dad says that's not what it means because it says in another verse that Jesus "tasted death."

"If they fall away"
My dad says this is talking about a christian who falls from the faith, and loses his salvation.
My youth pastor says it is talking about someone who falls away from becoming a christian, when he was really close.

"To be brought back to repentance, because to their loss they are crucifying the Son of God all over again and subjecting him to public disgrace."
My dad would say that if a christian falls away from their faith and rejects Christ, they can't become saved again.
My youth pastor says that if someone comes really close to being saved but then doesn't and completely rejects it, he can not be saved.
My question to that would be, how would someone who came really close to becoming a christian but didn't, be subjecting Christ to public disgrace if he/she didn't become a christian. I can see how it would work if this person was a true believer, but not if they weren't.

So I am faced with two opposing sides, one my church, and the other my parents. Both sides make sense to me, so for right now I'm just going to say that there are verses that support both sides. But hopefully in the future I will make a decision.

~Melody