18 yr. old Seeking advice

For some quick background info I'm bringing in around 900/weekly after tax with my 2 jobs

My portfolio is currently at 5.6k and I just started recurring deposits into a Roth IRA which is 25/weekly

Monthly expenses are 565 total which leaves me with a comfortable amount of money(3035) . I've been wanting to get a sport car (around 13k) as a way to reward myself for all the work that I've been putting in but I'm not sure if it seems responsible in the long term. My monthly payment would be around 350 for 48 months but I'm not sure if I can afford it. I'm just looking for some insight from people that have more knowledge than me since I'm still young and I know that I have a lot to learn.