If this concerns the potential future impact of the current pandemic, nobody can give you a definitive yes or no answer, I personally think that there is a moderately good chance international travel may be back in Spain by March, but I would not put money on it. I'm also not sure what would be the benefit of booking this trip so early in advance, unless it's all fully refundable ;-)
Otherwise do you have any specific itinerary questions, perhaps depending on where you are going, March may not be a good month weather wise?