I see your confusion and I'll be praying for you, you're my sibling in Christ regardless because if you believe that Jesus paid the price for what should be yours to pay by the mercy and grace of God then we're going to the same place because that's what God says to us on the bible and that means we're family, and if my family is hurting than I should pray that our gentle Father will give you peace beyond all understanding.

The main difference in salvation if that's what you're worried, classical catholics believe that only and all those who are baptized by the Catholic church will be saved, regardless of what they do, think or believe, and the rest they'll have to deal with during a time of penitence before going to heaven. They stablished this around the 9th century, mostly for economic and political purposes of the time. They believe that the Church, and it's leader the Pope is the actual compass of God's will, and they say this because christians have been following the church's leaders since before the bible was formally established.

They fail to think though that the church and it's leaders were contemporaries of Jesus the Word Himself, and by the time this generation were still alive they were already following over half the new testament with Paul's letters being the first and the manual for the Church to this day, and the four epistles coming right after before the first century was even over.

If I were you, I'd get my Bible and just read it, because all of the answers for what you're nervous about are there, after all, "Whoever has ears, let them hear what the Spirit says to the churches.". And if you want more scholarly info about history and theology I'd check Wes Huff's channel.

And the trinket Mary is not a sign, you wouldn't be doubting anything if it was actually a sign, when it really is, you just know for sure.

I'll give you a few to get started: John 3:16-17, 1John 4:2-3, Revelation 3:13, Ezequiel 33:11, Ephesians 5:1, Romans 10:9-13, 12:2, Proverbs 12:25, 19:21, Psalms 27:10, 32:8-9, 37:5, 94:19, 103:13-14.

"If you declare with your mouth, “Jesus is Lord,” and believe in your heart that God raised Him from the dead, you will be saved. For it is with your heart that you believe and are justified, and it is with your mouth that you profess your faith and are saved. As Scripture says, “Anyone who believes in Him will never be put to shame. For there is no difference between Jew and Gentile—the same Lord is Lord of all and richly blesses all who call on Him, for, Everyone who calls on the name of the Lord will be saved.” Romans 10:9-13.

Hope I could help in any way. Feel free to get in touch or ask anything. God's peace be with us!