Most learners worry about the wrong thing. Nobody is scoring your grammar. The common experience of trying Hindi in India is that people are visibly pleased and become noticeably more helpful.
If you look foreign, many people will answer in English — not to correct you, but to be kind and to save you effort. It is the single biggest obstacle to practising in India, and it is well-meant.
What works: मैं हिंदी सीख रहा हूँ, हिंदी में बोलिए — I am learning Hindi, please speak in Hindi. Said with a smile, it works almost every time, and it is worth memorising before you arrive.
Not a grammar mistake — a register one. Using तू with a stranger, a waiter or anyone senior is genuinely rude, where a wrong verb ending is simply a wrong verb ending. Default to आप with everybody and the risk disappears.
Heritage learners often get more correction, not less, and it can sting more because it comes from people whose opinion matters. That is affection expressed awkwardly, and it is usually worth saying out loud that you would rather be encouraged than corrected mid-sentence.
Reading an answer is one thing; being corrected while you say it is another. EkGuru tutors teach one to one from $6 a lesson, and most offer a trial.