25% is too much. These are money makers please avoid them if you are still a newbie.
Even if it was something like 1%, still chances are it's a scam. There's no such thing as guaranteed profit, even if you're the #1 best cryptocurrency trader in the world. Profit and losses will always fluctuate.
Anyway, kudos to OP at least you actually asked first before going in. It still boggles me how these types of scams still makes money these days.