Lovely to hear that you had a great time at REFRESH! Its always exciting to hear of a youngster wanting to make the right choices for the glory of God. I agree with @brianlalor that serving on Connect is a great way to get your feet wet in the world of apologetics and ministry. He has given some great suggestions. Connect is blessed by wonderful contributions from people from a variety of different backgrounds with unique experiences and qualifications. Some stay and serve on the forum for years and some come and go according to the season of life or calling. Online forums have a unique advantage of flexibility in terms of time and commitment.
The number one focus in apologetics always must be our personal relationship with the Lord. Its in that relationship that we will find the strength, love and commitment to others who need the gospel. Our growth in love of the Lord is a powerful apologetic and it alone will help us to keep the focus on winning people rather than their arguments. We can speak with more conviction when we have the knowledge not just in our heads but also in our hearts.
Apologetics can be overwhelming and we can be eager to increase our knowledge quickly. However, if we work at it too quickly, it will also fade quickly. Best approach I find is to take one subject at a time and grow in it, by reading books on the topic, making notes, perhaps answering questions here on Connect related to that topic. The more you engage with what you have learnt, the better the grasp and the communication. To start for example - after developing some basic understanding on topics such as arguments for God’s existence, resurrection, the Bible, you could slowly move on to specific questions that you encounter frequently in your circumstance.
As far as book suggestions, a good mix of both books that provide theoretical and practical knowledge would be good. Books by J Warner Wallace and Lee Strobel are a great place to start. Mere Apologetics - Allister Mc Grath, is also a great introduction to apologetics with a practical bent engaging the heart.
I hope this gives some ideas on becoming more involved in apologetics. God bless your journey!