You must tell her soon cause then she can take steps to prevent it re-occurring. I used to hide it from my parents and that made it way worse in the long run.
When you don’t tell those closet, the true extent, you emotionally isolate yourself, and them, further.
In my experience the more secretive and isolated the gambling and problems are, the longer they drag on for and the worse they get.
Maybe its best to do the unthinkable and tell everyone what an idiot you’ve been.. to break your own cycle?
wish you all the best and remember don’t try to beat the sports odds compilers – you are not a team of expert statisticians!