why was it hard for the texans to fit in with the mexicans.

There were many reasons why the Texans had trouble fitting in with the Mexicans; these reasons ultimately contributed to the Texan war for independence. Many Americans came to Texas, which was at first controlled by the Spanish and then by the Mexicans. There were several requirements that the Americans had to agree to accept in order to get land. These included agreeing to learn Spanish, becoming Catholic, becoming Mexican citizens, and obeying Mexican laws. Most Americans really were interested in owning land, not in following through on the conditions required for getting the land.
Mexico eventually realized that allowing Americans to come to Texas to get land was not necessarily in the best interests of Mexico. When Mexico closed its borders to American immigration, the American settlers in Texas weren’t happy, and they illegally continued to come to Mexico. The Mexican government also imposed high tariffs on American imports. Most of the American settlers believed that the American way of living was superior to the Mexican way of living. Thus, they resisted publishing their documents in Spanish, and they didn’t become Catholic. The relationship between the Americans living in Mexico and the Mexicans deteriorated and ultimately led to a declaration of independence when Santa Anna suspended the Mexican constitution.
https://tshaonline.org/handbook/online/articles/uma01