People take advantage of me... how can I be firm about what I want?

Asked by Sunshinegirl11 (1110) December 5th, 2016 from iPhone

I’ve always been labeled as the nice girl my whole life. I’ve always been so proud of that.
Now that I’m older, I still am nice, but I’m too nice. People take advantage of me. How do I be firm and set people in their place without coming off as a jerk? Especially when one of those people is my dad…

Mini rant… today I was planning to study all day for my finals in 2 weeks. I got a text from my dads girlfriend and she asked if I could babysit for her later this evening. I don’t want to but I said yes anyway because I know how busy she is. Then she texts me and says “great, I’ll drop Sammy off in a half hour.” Um what???? She said later this evening, not a half hour!

So I was pissed and out of anger I said to my dad “that was rude of her to ask me last minute! I would like a heads up!” Now, my dad puts his girlfriend on a pedestal, and the fact that I said something bad about her pissed him off. He very sternly then said “you can’t help someone else for once?! It’s that big of a deal that you cant help?! You are so selfish!”

I never talk back to my dad but today I was furious so I said “you act like I’ve never helped your girlfriend before! I helped her move into her new house, I helped her disabled uncle move from across the state at 10:30pm before, I’ve babysitted thousands upon thousands of times, including everyday before class last semester! I’ve drove and picked her up from the airport which is an hour away. AND I said yes to babysitting today. Who does she go to when she needs help? ME!! So don’t tell me I NEVER help out!” This shut my dad up and he hasn’t talked to me since.

That scenario just gives you a little idea of what is going on. Please help. I’m tired of this, I don’t want to be mean but being nice is no longer working….