ricmat,
I was raised Catholic and have been my whole life. I’m 15 and am now trying to go deeper into the understanding of my faith. However, so far the most “theology” I’ve read is C.S. Lewis’ Mere Christianity and I want to learn more. Does that help?
OK - since you started with CS Lewis, I’d recommend “The Great Divorce”. Not too tough or too long.
“How the Catholic Church Built Western Civilization” - by T. Woods. Another fairly easy read - not philosophy, but a wonderful summary of how we got here.
A Father Who Keeps his Promises - by Hahn.
Catholic for a Reason - Volumes 1, 2, 3. Also by Hahn and others.
Theology of the Body for Beginners - by C. West. I just read this recently and can tell you that it blew me away…
And these next 2 are quite deep - I wouldn’t start with these.
50 Questions on the Natural Law - by C. Rice (not so boring as it sounds).
The Imitation of Christ - by Thomas a Kempis.
God bless you for trying to learn more. If you ask (pray) God for things that are good for you, he will always give it to you. Ask him for help in understanding your faith, he won’t turn you down!