Well for starters you don't have to tithe, its up to you. Some people feel compelled to, others don't.
1) I'm only 17 and it doesn't make sense to give any money away because I need to save up for my future.
This is where selfishness comes into play as humans. Often sermons talk about how we love God and will do anything for Him.... unless it comes to our personal stuff. We see it as "Its mine!", but truth its Gods. Also your future is not clear. Your saving up for how you would like your life to be. BUt things can change. What if God calls you to go to another country? Then your future of your dreams wouldn't matter. THis doesn't mean don't save of course. But it means realize theres more to life then just living for ourselves.
2) I'm using most of my money on gas and groceries to save money for my parents which I don't think is a bad thing. So, if I tithe I will have less money for that stuff. Which will ultimately cost my parents.
As someone that lives at home I used to have that thinking to. And what I am about to say as always is up to you. Me personally after years of life not going great I decided to tithe. I took 10% out of each check I got first thing. The rest I paid bills with and all that. God can provide. One of the things in the bible talks about if you give, you often receive way more then you have given.
THis doesn't mean if you give $100, you will get $1,000. It doesn't mean you get a car. It means you end up having more blessings sometimes. You may not notice the blessings but they are there. Before I tithed my money was down to $10 a month to spend on myself. Mind you I am disabled.
Now? Well when I started tithing God gave me back so much I met a woman overseas and went there to marry her. Somehow that $10 turned into blessings that I lost count of. I've probably spent about $10,000 in the last year or so going there, marrying, paperwork for visas...etc. All after I decided to tithe again. How does $10 end up being $10,000? God.
Let me make it clear though. I am NOT saying if you give money, you get money or that theres always some big reward. But God realizes you gave what was his to begin with and he sees if you did it because you wanted to, not because you felt you had to out of guilt. So in this case he blessed me that I would give what little I had in tithe and had faith he would keep his promises in the bible.
3) What does the Church even need the money for? It doesn't make sense that Jesus who taught to not be about possessions and buildings. And His followers are spending so much money on exquisite worshiping places and etc. Christians should just worship in places that are free and instead of having full time pastors just have pastors preach once a week for free. Why should I spend money on something that the religion does not even support?
How do pastors get paid? How do they feed their kids or shelter them? How do missionaries get over seas or VBS classes get started for the unsaved kids? From things like tithe. God doesn't magically drop checks down from the Bank of Heaven for the church to use.
Do we need buildings? Not really but its not as simple as that. A building more or less for me means a place that is not just a building. Its somewhere special where we can all meet and praise God and listen to the word. Even in 3rd world countries they tend to have small buildings or even huts they build as a church.
Finally, if my heart is not in it then Jesus probably doesn't even want my offering anyways. He speaks many times to the Pharisees and other people about how He doesn't want their offerings and they are worthless because they do not truly want to give. And, God can get whatever He wants and has everything. Why does He need my money?
Jesus again doesn't say you have to tithe. He has no need for money himself since He after all is in heaven where money doesn't matter. But your money IS his money by default. So your giving Him his own money out of love to show Him you have faith and love in what He says. And by giving your money helps diffrent things like mentioned above such as ministries.
He has everything? Everything what? Materials only matter to us on earth. THeres no currency in heaven. No stores. No fast food places. He doesn't need anything because Hes God. For lack of words its like if your dad asks you to put away the dishes. So you listen to him and do it because he asked or do you not? Gods asking you to do something, its about faith, trust and so on. As mentioned many times though in the case of tithing. You are nor forced to or required.
Lastly reading everything you it sounds more like you are all about you. Its your life, your money, your stuff and you don't want to anyone to do anything that my effect you. Your young yet but it doesn't excuse your actions. Just because you accept Jesus into your heart doesn't mean thats it, you don't have to do anything else as a christian. It also doesn't mean you can live a worldly life because you are saved now.
If anything a christians life is not easy because we have to die unto ourselves. Which means give up what the world says life is about and surrender to God. We have to be slaves of righteousness. And you can only serve on master. Is it righteousness or selfishness?
