One of the easier ways to both fund and prove to everyone you have the desire is to get a part time [if you are continuing your education] or a even full time job with a flying school doing anything at all, sweep the floor or whatever.
You may even get a discounted rate for your PPL training as an employee, or at the very least be able to 'pay as you go' rather than be forced to fork out a lump sum.
If you can do this whilst living at home then all the better as the costs of living on your own are just not going to give you the spare cash to fund your PPL in your spare time.
Get your PPL this way and both your parents and potential employers will look at you a whole lot differently than they do now.
GOOD LUCK!
PS - a quick 10 point reality check.
1. Getting a job a a FO with an airline is not easy [check all the posts on here]
2. You don't yet know if you are capable of the ATPL rigors yet so PPL should be your first taste of what is to come
3. At the moment you will need to get 500-1000 flying hours, after you get your ATPL, to have a hope of getting a FO interview. Getting a job as a flying instructor is the only realistic option to build and pay for these hours
4. You may well need to pay to obtain a 'Type Rating' [TR] to secure a FO job
5. Working on an airfield gets you experience beyond that of flying which can be very handy and maybe pick up some contacts in the industry which you might need to call on in the future
6. If you go the 'Modular' route to your ATPL then expect to pay 40k just to qualify and we are talking lump sums of cash for each section here
7. If you go the integrated route then it's around 70K as a lump sum
8. Unsecured loans are not an option at your age with no job
9. Banks are starting to refuse funding for integrated training for ATPL and you are required to start repaying this loan [if you can get one] as soon as you qualify - job or not.
10. Flying Instructors earn about 10k a year give or take