Absolutely. Story issues aside, it has the best gameplay of the series. If the story starts to bore you, stop playing the main missions and play through the entirety of the Citadel DLC. It's a far better ending to the trilogy than the actual ending, even with the extended cut.
The common refrains of Be Yourself and It Gets Better seem a little disingenuous when you add family to the mix. But trust me on this. If you put your happiness first, and your family really loves you, they'll have your back when they see that you're living the life you should be living.
I don't think your sister's reaction was an accurate reflection of how she feels. I think it stems from a part of her that feels like she's losing her brother. Give it time, and she'll be able to articulate how she really feels. Once she realizes that you're not a different person, but rather living on the outside the way you've been feeling on the inside for your entire life, she'll be in your corner.
I went through something similar a while ago. If you want to see how everything worked out for me, you could browse through this thread. For what it's worth, I think you sought help in the right forums. The Giant Bomb community can work some serious magic.
At the retailer I work at, we have a binder from Nintendo reps about how to properly sell Nintendo stuff or some shit. There are a few fun facts in there, notably one about how that garbage from the movie with Mario being Mario's first and last name is true. If this Yoshi garbage is canon, that bullshit has to be canon too. It comes from official Nintendo marketing material.