Your presence (appearance) is important. In this physical world we make judgement about what we see all the time, in an instant and that includes people and what they look like. Some people get excited about clothes and others, not so much. Here are some instances where appearance (what you are wearing) matters:
a job interview
going to college - at least in the beginning
hanging out and wanting someone to notice you
the first date
the second date
the 25th date
meeting your partner's family
your wedding
all the days in-between
a funeral
going to get your kid from school
shopping at the grocery store
working out
a party
a celebration
life stuff
There are many occasions to look put together and I believe - all of the days you show yourself to the world - you should be put together. I have seen firsthand how buying a car, meeting my husband, teaching a class, going to a grandkid play, etc. has made a difference in how I am received and accepted. Some might think there is something superficial but there is not anything superficial about dressing your human body in a way that shows you care. It actually allows you to be you. You will find you get accepted and now you can just be you.
This is one of my favorite subjects because I love style and fashion and clothes and shopping. What I don't like - high prices. So I have gotten really good at consigning - giving and receiving. Here are a few outfits that cost less than $50 each - top, bottom, and jacket. The one item I like to buy new is pants because I have a unique shape. Put together 3 special outfits that you wear to the concert, date, work event, etc. There is nothing worse that a closet full of clothes that don't fit and don't go with anything. That is where a capsule wardrobe can help. You have 3 pair of pants; 2 tops that go with the pants; then a piece or jewelry or a jacket to complete the outfit. You basically have 10 to 15 pieces that go with each other.
Know that being mindful means knowing that you need to look pulled together and have a functional wardrobe.