Undermineing is as parents

An

I have a 20 month old daughter who is about 25% Hispanic. My mother in law is 100% Hispanic and ever since my daughter was born my MIL has spoken to my daughter is Spanish. My daughter’s speech is just now starting to come in and we have tried to tell my MIL multiple times to please hold off on speaking in Spanish until we can get our daughter’s English more consistent instead of the toddler gibberish that she talks. My mother in law after mentioning it to her again last night about speaking Spanish to our daughter she completely undermined us and told us no, and she used my husband as an example as to why she won’t stop. My husband can speak in English and in Spanish and according to my MIL he could flip between the two languages when he was little when talking to two different people. I am at a lost on what to do. I do want my daughter to learn Spanish and I know that young kids can learn different languages easier that when they get older I also know that it can help her in the future with getting a job because she will be bilingual. How do I go about expressing my feelings because my MIL doesn’t even listen to my husband? Are we asking to much? Are we in the wrong for not wanting her to learn Spanish while she is still trying to figure out English?

Thank you Lauren and R! I am concerned because I had speech delays when I was younger and I do not want that for my daughter.