not really! im a girl and I just wear my t shirts (stock up at freshers fair dude) or a dressing gown if I need to go to the kitchen, no matter what flatmates you end up with, by second term your not really gonna give a damn what you wear in the morning. Dont get into the habit of walking around in your pjs outside though, even some jeans over your sleeping shirts and a jacket will make you look presentable and also you wont get any lazy habits youd probably have to kick after one year. I live on a campus and the only time I see people wearing pjs to the store is about 2 am in the morning, no judgement there! But if its 10am and theres people on there way to class you bet your ass theyre gonna judge you!
(ps. pjs are the first thing to end up in the bottom of your laundry basket, youre gonna end up with only boxers by the end of the term anyways)
(pps. keep a thick coat, some bottoms and shoes near your door at all times, theres gonna be a 3am fire alarm and you will only have a few minutes to exit the building)