Solo travel in Barcelona

I’m 45F and I’ll be Barcelona at the end of March for a few days. I haven’t been since I was at uni and I’m trying to figure out what neighborhood/hotel/hostel to stay in.

I want to be able to walk alone at night, and hopefully explore mostly on foot during the day, as well as using the metro. I love specialty coffee and pastries, artisan crafts, markets, museums. I’m not too worried about the beach because I live in a similar climate.

I speak Spanish, have traveled a lot alone, like to meet people. I’m reluctant to stay at a hostel because I feel like I might be too old. My budget is around $150/night.