Were my parents joking?

OK so I like my stepcousin, she is a second cousin by marriage meaning my mom's cousin married her mom while she had her from a previous marriage. I liked her immediately when I met her. when I first saw her my mom tapped me asking if I thought she was cute. she said if I need a girl to go to dance with for homecoming, I could ask her. However, I asked my mom if I could date her. She said "Well you could, but her father might kick your ass." A year later when I saw her again, I asked my mom again and she said the same thing. Also, when I saw my other cousin who is biological, she said "that one you can't screw." I don't know if that signifies if I can screw the step cousin or not. And when I finally started going to the same school as her and she saw me, my mom said that she saw me and she said hi and my dad jokingly made a blowjob gesture. When I finally told my mom that I like her, she was like "there's a lot of girls at that school, why did you pick her?". He also said that blood related or not they're still a taboo and told me it would feel weird and asked me if I really wanted the family to know what we're doing together and her father will kick your ass. My dad also found out and he laughed. he also said "she's your cousin, I wouldn't try ever.". Mom then told her her step grandma who is biologically related to me and said that I think she's pretty. She then replied "well they are blood related" and my mom said "well you know they're technically cousins right?". My mom said "I invited them over for holiday cheer, planting a seed for yeah.". I also don't know if that was a joke. The day after that my dad said "she doesn't want to date you, even if she did like you. She might have sex with you, but not date you.". So where my parents joking about me dating her or where they OK with it. Please comment.