Is it worth it to go to Spain if I’m only going to Barcelona?

I’m a solo female and I would like to travel to Spain with a reputed group just to be safe. I also don’t have much knowledge on Spain, I honestly couldn’t have listed any “famous“ monuments in Spain other than the major cities. I found a short trip that just goes to Barcelona. I need a short trip because I don’t have much leave. It will visit places such as La Sagrada Familia and Park Guell. Will I be missing out on a lot of Spain if I don’t go to Madrid or Seville or other places?