Can't Create Families in CAS

I had a sim I made who was originally a Young Adult, but decided to play a different storyline and made her a Teen instead. I subsequentially made her parents from the genetics bar; first her mom and then her dad. Both parents were Adults and the OG sim a Teen. When I went to adjust the dynamics in the relationship tab, the Teen was only labeled as a "Household Member." When I went to try and change it, the OG sim can only be either of the parent sims' sister? I have tried a lot of work-around tricks to get it to change and it nothing works. I haven't tried it in any other household, but if I do and the same thing occurs I will report back. I really want to play with family dynamics for this families story but it I simply can't.