They asked me: “You’re saved, but are you a disciple?”

I’m worried my love might grow cold and that I won’t stand firm until the end (Matthew 24). What can I do? I heard it’s not enough to be saved and now I need to be a disciple. What are your thoughts on this? My son is convinced we need to go to church on Saturday because of the Sabbath. Is this true? What are the names of the Holy Spirit? There are no “levels” for Christians, but what about the apostles? If I’m really saved, then why do I constantly get sinful thoughts flooding my mind? Is Jesus only drawing some people to be saved, leaving others with no invitation and no chance?