The devs are actually really good about handling all of that. It will work fine. You can do stuff in any order, and you usually see different scenes play out if you did something differently, and there are usually multiple ways to solve a lot of the puzzles (like I mentioned before about a couple other ways to get the key from Ashley).Only "problem" was that I hadnt invited Vickie to the party, and I gave Ashley the flower, and now I dont know how the quest that Vickie gives you, where you have to impress the girls, will work.
I remember you needed to give Ashley the flower for that quest, but I only had 1 flower....oh well.