Hate to break it to you, but the bottom line is this: if throwing a hammer of a curve was easy to do, then every pitcher would throw one. Not every pitcher has been blessed with the ability to throw a good curve. That is why you see pitchers turn to “the other” breaking pitch: the slider. You’re at the age where your arm should be able to handle the stress of throwing it, and it is not as difficult to throw as a good curve.
I throw a loopy curveball that comes in at 67-70 mph. If used correctly, it still can be efficient. I have found that it is useful early in the count against first pitch hackers and as a get-me-over strike. Most hitters will not be swinging at off-speed on the first or second pitch of an at-bat It can also be used to backdoor hitters when you get deeper into counts.
It all comes down to the quality of your other pitches. If your other pitches are solid and can get swing-and-misses, then you don’t need a hammer. If you need a strikeout pitch, then a slider may be the way to go. Ultimately the decision is up to you.