I would recommend you read a book named "The Richest man in Babylon."

The recommendation they cover again and again is to live beneath your means and save as much as possible.

(You did that... Good job!)

Then the recommendation becomes "Invest the money with a professional who knows their field and has a smart plan." They specifically mention to avoid persons who are looking to enter a field they don't know.

If you are that person awesome!

...but, you're probaby underestimating what you don't know.

The good news is that 15k is likely enough money to pay for the initial mistakes you will make as long as your plan is simple and inexpensive.

Lets put it this way. I have run a computer business for 10 years. I would estimate I have earned and spent almost $250,000 getting to know business and have survived on a remainder of about 20-30k/yr net on average. (admittedly 5 years of that was a small part time business with no expansion goals)

My oompany is pure profit when I am the only person involved. I go out, get work, do it, get a check. I know my industry well (my skills are general, not specialized) and am a great sales person.

The expensive side of the company was learning to deal with employees, contracts, debt, balancing for intelligent expansion and maintaining liquidity.

The business paid for all of this as I earned it before reinvesting it.

...

lots of words leading to:

Find someone who already learned this stuff. Invest to help them grow after they have !!proven!! they know this and are in a place where they will pay your money back whether they succeed or not.

good luck.