'Isn't a Christian just a good person or someone who believes in God?'
God wants us to be friends with him not just good enemies. It is not good enough to just to believe God exists (even some people who hate God believe that). We actually need to apologise to God for rebelling against him, and thank him for the death of Jesus which pays for our rebellion. We should then ask God to help us live with Jesus as our Lord. We are to live in a way that pleases God because we have been forgiven, not in order to be forgiven.
'Do I have to go to church to be a Christian?'
The short answer is No! Going to church doesn't make you a Christian any more than walking into a garage makes you a car. A Christian is not defined by what they do for God, but by their trust in what God has done for them in Jesus. God is not after church attenders; he is building a family. Of course, once you are a member of his family it will be natural to want to meet with other members of the family, learn together and encourage each other and church is a great way to do that.
'Aren't Christians just a bunch of hypocrites?'
Christians don't claim to be perfect and we are aware that we often don't live in a way that pleases God. Ultimately, though, you should decide about the value of the Christian faith not on the bad performance of its followers but on the basis of its founder - Jesus. The accounts of his life in the Bible (Matthew, Mark, Luke, and John) show he was no hypocrite, he perfectly practised what he preached. Read one of them for yourself and check out his life and claims
'Hasn't science disproved Christianity?'
Science assumes order and uniformity in the world, and provides ways of understanding what normally happens. It doesn't 'disprove' the miracles recorded in the Bible, since these are examples of God at work in the world in 'unusual' ways which we would not be able to predict. Science doesn't set out to answer the bigger questions such as 'Why are we here ?' and 'How should we relate to God?' and cannot do so. To find the answers to these questions we need to look at what God himself has said in the Bible.