I would keep the account since it’s aged. The number of followers (100) is low enough that your current engagement rate isn’t critical. I would heavily engage with my current followers posts so you can rank in hashtags. In general, I would engage with people who like your competitor’s posts so they’ll follow you
as @Powerlifter said, the number of followers is still low to judge the engagement, and since the account is aged I wouldn’t leave, but instead grow it more and more, you can start with the follow/Unfollow method and you need to engage more and more with users.