My doctor thought I wouldn't be a good Spanish teacher for him. His brother-in-law is from Mexico, and he would like to visit and be able to chat in Spanish. He thought that since I'm from Spain, the Spanish I would teach him wouldn't help him talk to locals in Mexico City. This is a question many people have when they start learning a language. I'm here to tell you it's not as important as many think. Choose the variety that’s most convenient (most likely dictated by your teacher or textbook) and you'll figure out the variety you need in the future.
We often don't know where we are going to use the language. I learned English in Spain. Back then—social media might have changed this—we used to learn British English. My English professor in college was from Manchester, and we often listened to BBC news in class activities. When I finished college, I moved to Greencastle, Indiana, and the difficulties in surviving were unrelated to me speaking British English.
It didn't take long to learn that the letter Z was pronounced as "zee" and not "zed". When I spelled my last name—Lozano—to the cashier at Forever 21 in downtown Indianapolis, she didn't understand "zed". I gestured a Z Zorro-style and she said: "Oh, you mean zee?" Did this mean I studied the wrong English? Not at all, it was an opportunity to expand my vocabulary and knowledge of the language.
The dialect issue isn't exclusive to non-natives; native speakers adapt to different varieties all the time. Think about it: if you're a monolingual English speaker from the US traveling to South Africa, you don't worry about communication before landing in Johannesburg. You might encounter unfamiliar words and expressions, but you'll learn them naturally through context and conversation.
I'm writing this post from Mexico, where my family is visiting for the first time. They're already picking up new words, especially for foods they've never tried before. This isn't as challenging for me since I've visited Mexico several times and regularly interact with Mexican Spanish speakers in New York. Learning a new variety of your language does take some effort—and yes, it might be a bit harder in a second language—but adaptation happens naturally with exposure and practice.
Should you care about the language variety you learn? In most cases, not really. Unless you're in a highly specialized field—like acting, where language variety signals belonging to a community—it’s not something to stress over. Even translations sometimes create a “neutral” variety for practical purposes, but that's a concern for advanced speakers and highly specialized cases. Some languages, like Arabic, are different; a Saudi speaker might struggle to understand a Moroccan one when both use their dialects. But Spanish? Don’t let variety scare you off. Start with whatever variety is most accessible to you. As you gain exposure, you'll naturally expand your knowledge and adapt to new varieties.