There is nothing wrong with making your own engine in fact it can be a good choice if you're able to stay focused on your goal.

A lot of people who want to make games get caught up on the engine aspect and never end up making a game because they look at what other engines have and assume that they need those features.

Instead of asking what features their game needs.

So if you're making a game and want to use a custom engine then make sure you only build what your need and not what you want.