Life is short. You'll be in the Sierras. Enjoy every minute, even those pesky other people!
Hey, you asked for advice, that's advice!
I love the sierras and got to go there for a one week backpack for the first time in 28 years, about 3 years ago. It was great, but some in our group were annoying to me. I tried to just enjoy it despite them. It was not that hard to do.
One thing I did that helped a lot with that. I bought a new big agnes solo tent, and insisted on using it! So I had some nice privacy, such as on a day when we hiked only 4 miles in the rain and set up camp at Lower Crabtree Meadow, and I had a good book to read and some hot chocolate and just hung out in my tent and read my book. I was semi-aware that two of the other women, who were sharing a tent, were having a personalitly conflict, but it didn't have to affect me.
Oh, and then there is the bear canister. Get a big one. Make sure it fits in your pack! Pack everything a couple weeks before the trip into the bear canister so you will have plenty of time to refine your packing in that thing.
Be self-sufficient. If you must share anything, let it be your stove, but make the other person carry their share of the fuel.
Life is short, enjoy!