You should be learning this language because it is the language Allah SWT revealed His final revelation in. Allah SWT mentions the importance of Arabic in understanding the Quran in a number of places. In Surah Hud He says:
“No doubt, We revealed it as an Arabic Quran so that you might understand.”
When you make understanding the words of Allah SWT your primary intention for learning Arabic, then the doors to comprehending this language will open to you, God-willing. Being able to understand Arabic texts on fiqh or aqeedah should only be secondary to your focus on the Quran. Ultimately, all branches of Islamic knowledge are simply attempting to better understand the Quran.
This language is open to anyone who is sincere - as evidenced by the fact that the greatest grammarians in our history were non-Arabs.
As you learn, your increased understanding of the Quran should bring you closer to Allah (SWT). Allah (SWT) tells us towards the end of Al-Baqara:
“Be conscious of Allah and Allah will teach you.”
May this be the means through which Allah (SWT) opens His doors of knowledge upon you and the means to a lifetime of learning.