Is it normal being in an relationship with my cousin

My mom and aunt to this day work for the same company, the same hours and the same location. They started when my female cousin and I were both 12yrs old. I'm a guy but since we were kids we bathed and slept in beds together so we always seen each other naked. At 12 ours mom's started working nights. They figured we would be safe with each other by our selves until morning. We instantly started exploring each others bodies, playing games and dry humping. We played boyfriend and girlfriend when they left for work. Over the years we eventually had sex and started an undercover relationship. Somehow another cousin (jealous probably) found out and our family basically disowned us. Should we have never started our relationship?