I would like to have earrings, maybe be tan, and be in better shape, plus I would like to whiten my teeth. It sounds ludicrous, but are these things wrong according to God if I want them? If I were to do these things, I feel like they would be holding me back for some reason. I feel like I've kind of hit a brick wall with my relationship with God, even though it has only been two weeks. I kind of feel that God is waiting for me to actually go out and serve Him. Since my true conversion, telling God I was His and I would serve him, I haven't served Him with ministry yet due to laziness on my part. I feel like He is waiting for me to do so. I feel like He is saying "We just met, but I am waiting for you to go out and serve me before we can get better acquainted. Show me that you love me." What do you think is holding me back? Is it the image thing: earrings, better shape, etc. Is it laziness? What is it exactly?
What is it that causes people to put their feelings ahead of their knowledge and understanding of God's will? Feelings can be manipulated. You can go to a movie and start crying over events portrayed, but does that mean you are actually having a lousy day? And this is being done by people putting on an act in a made-up story!
God has told you what He wants of you. He wrote it down in the Bible. So let's drop the feelings stuff, and let's look at what God has said.
First, in serving God, there are many different ways a person can serve the Lord. Teaching is just one way. "For as we have many members in one body, but all the members do not have the same function, so we, being many, are one body in Christ, and individually members of one another. Having then gifts differing according to the grace that is given to us, let us use them: if prophecy, let us prophesy in proportion to our faith; or ministry, let us use it in our ministering; he who teaches, in teaching; he who exhorts, in exhortation; he who gives, with liberality; he who leads, with diligence; he who shows mercy, with cheerfulness" (Romans 12:4-8).
Teaching is important work, but it comes with major responsibilities. "My brethren, let not many of you become teachers, knowing that we shall receive a stricter judgment" (James 3:1). When you take up the mantle of a teacher, you are also agreeing to be responsible for what you say to other people. That means you need to learn what God wants to be taught instead of talking about what you want. "If anyone speaks, let him speak as the oracles of God. If anyone ministers, let him do it as with the ability which God supplies, that in all things God may be glorified through Jesus Christ, to whom belong the glory and the dominion forever and ever. Amen" (I Peter 4:11). Because if you teach someone falsely, God is going to hold you accountable for that lost soul.
I'm not surprised you aren't ready after being a Christian for two weeks. I would be more surprised if you were able to do it after such a short period of time. "You therefore must endure hardship as a good soldier of Jesus Christ. No one engaged in warfare entangles himself with the affairs of this life, that he may please him who enlisted him as a soldier. And also if anyone competes in athletics, he is not crowned unless he competes according to the rules. The hard-working farmer must be first to partake of the crops. Consider what I say, and may the Lord give you understanding in all things" (II Timothy 2:3-7). Every job on earth requires preparation and training. Preaching is no different. But if you are serious about your commitment, then go find a preacher with whom to work. "And the things that you have heard from me among many witnesses, commit these to faithful men who will be able to teach others also" (II Timothy 2:2). And pull out your Bible and start learning. "Be diligent to present yourself approved to God, a worker who does not need to be ashamed, rightly dividing the word of truth" (II Timothy 2:15). So, yes, you need to get into shape before preaching but it is the spiritual shape and not physical shape. "For bodily exercise profits a little, but godliness is profitable for all things, having promise of the life that now is and of that which is to come" (I Timothy 4:8).
What should you study? Start talking to others about the Lord. You will rapidly find out that there is a lot that you don't know, so you hit the books and discuss the issues with more experienced preachers. As you fill in your gaps you will become more effective in the cause of Christ.
While it may be nice to look good, your looks have nothing to do with the spreading of the Gospel. Only if your looks were a hindrance to talking with people would I suggest that you take some measure to remove that stumbling block. But believe me, a person who is hungering after the truth won't care if you are pale and a bit thick around the middle. Consider what people said of Paul, "'For his letters,' they say, 'are weighty and powerful, but his bodily presence is weak, and his speech contemptible.'" (II Corinthians 10:10). It might seem strange, but Paul agreed. "I was with you in weakness, in fear, and in much trembling. And my speech and my preaching were not with persuasive words of human wisdom, but in demonstration of the Spirit and of power, that your faith should not be in the wisdom of men but in the power of God" (I Corinthians 2:3-5).