God spoke to us by prophets in the past, but now most fully by His own Son, who is exactly like Him, and far superior to angels. Angels serve those saved. Jesus did the saving.
The first covenant with Moses was mediated by angels, so how much greater is the covenant brought to us by Christ? God didn't subject the coming kingdom to angels, but to His Son. Jesus' suffering doesn't demean Him, but He became like us to save us.
Jesus was faithful, as Moses was. But Moses was just a servant in God's house; Jesus is the heir. WE are the house! Be careful your heart doesn't become hard without realizing it; sin is deceitful. You can share in Christ and then rebel and fall away; it happened to many in Israel after the Exodus.
Enter God's rest by believing the Gospel you heard. Many failed to enter before; God holds it open for you to enter now. The Word of God can discern whether you have entered God's rest in faith, or whether you are just faking it.
Jesus is a greater high priest than the high priest in the temple in Jerusalem. He prayed for His people while on earth, and was anointed directly by God for the office, in Melchizedek's line, greater than Aaron's. I'll have to skip over some of this since you aren't mature enough to hear it yet, though you should be by now.
If you forsake Christ, having once partaken of His Spirit, you can't be saved. But we trust that you will persevere and inherit God's promises to save you in Christ. Our anchor of hope holds within the heavenly veil, where Christ is at God's right hand.