My blessed Angel wife took me on with all my sons ranging in age at that point from about 12 downwards and I took on her son who was 13. Huge adjustments for everyone, but we always respected each other, communicated, didn't get our hair off, and if there was a big problem about anything we adopted a "talking stick" method whereby only one person speaks at a time so everyone is 100% heard out ( people are usually reasonable if they think you are listening to them).We also kept a united front no matter what. We have since had our 8 year old daughter, have had an ex's 3 year old son come to live with us and now have a baby girl as well whose nearly 7 months old.Teenagers are horrible creatures (lol) and they have a hard time round that age dealing with themselves. Keep a clam head, respect them even when they don't respect you, lead by example and all will be fine ( eventually).