How realistic was the demo?
Was the demo data-feed identical to (and on the same server as) the live feed you’ll be using, with money on the line?
Do you mean “testing for 3 months,” or do you have a decade’s backtested results as well?
How many trades in total have you backtested?
With what win-rate, average win size and average loss size?
Sorry to fire questions at you! 
But this, honestly, is kind of the “absolute minimum information” any real and experienced trader is going to need, to start from, to be able even to try to answer your question sensibly and/or sensitively.
I respectfully advise you to be VERY, VERY careful of people who may just give you some semi-random figure without knowing (or asking for) all that information!!
And even then, the answer’s still going to be heavily dependent on the extent of your risk-aversion/risk-acceptance, on how easily you can afford to lose the $15k, and on a number of other very subjective factors, you know? 
But above all, well done for so quickly developing something that looks so promising! 
And welcome to the forum, too.
By the way, this very recent thread will interest you. Probably. Click the green words in the link below. The thread contains 9 sensible replies and 3 stupid ones (that’s a really good proportion, for a trading forum thread, so it’s a compliment to the thread, not a criticism of it! See if you can tell which are which?!).