Pasta in mushroom sauce not gone my way...

The recipe we followed, but we left out the wine http://www.foodnetwork.com/recipes/everyday-italian/rigatoni-with-creamy-mushroom-sauce-recipe/index.html

Today me and my friends decided to make pasta with mushroom sauce. So we went to the grocery store got all the ingredients we needed and started cooking it, everything went well until my sister came into the kitchen. When she came in the pasta was nearly cooked and we were working on the sauce, while I was getting the vegetable stock ready she decided to put the beginning stages of the sauce (mushrooms, shallots and garlic) and start mixing it with the drained pasta, we still had to add water,vegetable stock and cheese. I became furious, for once me and my friends were successfully cooking a meal rather than messing it up and having to resort to boxed mac & cheese. My friends backed off as they saw my face turn red as my sister added the vegetable stock and pasta water to the pasta, I was mortified I was about to let the stock reduce a bit in another pan before adding it so that the sauce would be thicker. My sister stared at my red face not even apologising for what she had done. Okay I know i'm over reacting and that it was a mistake but I really wanted to show my friends that I could cook. So my sister came in took control ruined the dish and left. Alright so she added the cheese and the sauce wasn't horrible and she added more cheese to thicken the sauce, but she didn't even apologise she just kept making it seem like I was over reacting, I hated how she could do that but as we tasted the pasta, it actually wasn't bad but the sauce was watery and i felt i could taste the vegetable stock. My friends didn't hate it and neither did my sister so overall it was'nt ruined, and I was  glad because I did not want to have to cook another meal again, I was starving and just wanted to eat. I was also mad that my sister took control of cooking the meal, I wanted to cook I was Waiting since yesterday to cook with my friends, I guess it just hurt my pride,and I was over reacting.
              M