Growth for Christians is a lot like tending to a plant: we water it, make sure it gets sunlight, till the soil, weed it, but ultimately only God can cause the growth to take place. As Christians there are a number of ways we can nourish and till the soil of our hearts for growth to take place, and the Holy Spirit uses those disciplines to cause us to grow. As we read the Scriptures, spend time in prayer, share our faith, and fellowship with other Christians, growth happens. Doing these things in and of themselves doesn't make us better Christians, but God uses these to change us from within.
As you consider getting connected to a small group or study group know that God will be working on your heart to transform you to become more like Jesus. 1 John 3:12 says "we are already God's children, and we can't even imagine what we will be like when Christ returns, but we do know that when he comes we will be like him." God's purpose for you is to become more Christ-like, a lifelong path of growth for every Christian!
It's part of our mission statement at St. Mark's - to grow to become like Jesus! Take the plunge into a life of growth - it's an exciting and challenging place to be!