if the niche is tough it's normal. But I would still take a closer look at the keyword (assuming that your domain name is not penalized, obviously, in which case you would wait until you grow beard and you still wouldn't rank).
Seriously, though, analyze your keyword in Ahrefs and take a good look at the URLs ranking on google's 1st page, see what type of content they have, how well optimized it is, how long it is, also check the number and quality of the backlinks that those URLs get, and then decide whether 4 months is a long enough period to wait