If I spend 30mins everyday how long should it take for me to sing at good level

Hi, Ethan! That's a difficult question to answer, since each person's experience and skill level is so different. With consistent practice, look for improvement over weeks & months, since any new skill takes time! Instead of looking toward a future goal of "good", I encourage you to focus on "better than before". Our competition isn't other singers, but our past self. Please see here for an article on this topic: https://www.30daysinger.com/blog/getting-better-fast-when-will-i-hear-improvement-in-my-voice.