Think about your wardrobe and what you tend to wear at the times you’d be using the bag, would be my advice.
Also, can you go into the shop and look? Some of the colours and styles look very different in real life. You might surprise yourself and fall in love 😁. John Lewis will order any that you ask for if they don’t have them in stock so you can go back and try them out.
I have a couple of them, and I ended up going for very bright colours because I mostly live in plain black clothes. I get so many compliments on one that is a sort of bubblegum pink, and I really didn’t go meaning to buy pink, I was thinking of lilac or pale grey.
it’s a lovely thing to be buying, enjoy, take your time, and love using it, OP!