A bit of an impossible question to answer, I'm afraid, as we know nothing about your income, your lifestyle, your health state and so on.
Hundreds of thousands of Brits have made their homes in Spain and, contrary to perceived ideas, the majority are under pensionable age. A couple can live, fairly comfortably, on €1000 a month but this would be difficult if you run a car, pay rent, need to pay health insurance for pre-existing conditions or even find you can't give up UK luxuries like baked beans or Iceland frozen gateaux.
Even if you get a cheap flat rental (and some studios go for around 200 a month) your utility bills will be at the minimum 100 euro a month (more like 150+ if you don't constantly scrimp).
However, we are all different. I would say go for it as you may constantly regret it in future if you don't. You'll certainly know after 6 months if it's working out for you and 6 months is not much of an investment.
We retired here well before retirement age (but have now reached it). I wouldn't have changed what we did for anything but we did have good savings and pensions to back us up. It hasn't worked out for some people as the didn't realise it's not a permanent holiday or missed family more than they thought.
Best of luck whatever you do,