It is very easy to look back on life and say “I wish I had done this” or I wish I hadn’t done that” but you cannot learn from mistakes that you haven’t made. Take risks. Regret things you have done rather than things you haven’t. Remember that life is short and you have plenty of time ahead of you to settle down. Experience the dysfunctional relationships so you can truly understand when you have found the right one. See the world and keep your sense of wonder.
You will be working for a long time so find something you love to do and figure out how to make a career out of it. Don’t let others define your path for you. Don’t listen to the well-meaning advice that chemistry will be more useful than a foreign language. Trust me, you will never need chemistry again!
Above all, be happy and see the positives in everything that you do. Never forget how fortunate you are and always compare yourself with those less fortunate rather than those more fortunate.