Hi @jackct923, welcome to the forum! If it’s any consolation: it is very normal to struggle with this, and a lot of others have asked this question before you.
Old faithful is a great strumming pattern for loads of songs, but not so much for songs with a chord change in the middle of a bar. It is often recommended here by one of the Justin Guitar teachers, @Richard_close2u, to do a downstrum on 3, just in the bar with the change. You could just do 4 downstrums in that bar. It’s less complicated than it sounds.
But since you’re still very early in your journey, you could also use another strumming pattern for the whole of songs with 2 changes in a bar. It’s not mandatory to add old faithful to the song exercise. But it is of course a good exercise 
Keep up the good work!