I would go so far as to say if they can win both of their next two home games and then win the game against Barcelona in Barcelona, I believe that they are a potential title winner. Yes it is still a long way to go, but if they get a perfect 9 points out of 9 in the next three games, Girona has the potential.
It seems to me that it is too early to say that Girona can win La Liga, precisely because their rivals are Real Madrid and Barcelona. These teams have much greater capabilities, a deeper bench and much greater financial resources. I know that we all remember the example of Leicester in the Premier League, when everyone followed them, but it seems to me that this happens very rarely and if Girona cannot find proper funding and strengthen the team in the transfer window, then this goal will be difficult to achieve for them.
The financial resources literally help nothing because there won't be this one huge transfer in the winter transfer window that puts the team upside down and turns it into a 20% better squad. Those are mostly smaller transfers to fix some issues that occurred due to injuries or other players being out of form.
But when you read my post you will see what I said would be a condition for me to start thinking that Girona could have a chance. If they win the next two home games and then beat Barcelona in the Camp Nou, that would make 43 points for them after 16 games and a 7 points advantage over Barcelona. With that massive winning streaking backing up their form by then, I believe that people will start considering them a potential team to win the title. Real Madrid would still be the favorite then and nobody is arguing against that, but still.