Kiev23,
I've had a glance over your past posts and I can see that you are looking into the flying career.
Where to start? Well, to be honest, the best starting point is that no-one, and I repeat, no-one, can answer that question for you but yourself. I don't mean that as a put down or a dig but purely that, on this forum at least, you will get a vast amount of opinions that reflect the posters personality but not yours.
All trainees are different. When you instruct the best, wisest and healthiest attitude to take is that the next person in the seat next to you is a new experience. How YOU, not the guy you are talking to but YOU, react to stress, pressure and constraints be they time or cash will reveal more about you than any amount of group therapy could ever do. You will react however you react. Many people collapse under pressure, many thrive. Many take the 'I must learn, verbatim, every single line in this manual' approach only to be blown out of the water when something doesn't go to plan. Many also take the 'I know the lot so don't try to teach ME!' approach. They tend to get bitten quite quickly when the scenario develops quickly beyond their fledgling understanding and the instructor sits back and lets them handle it.
Until you put, or even don't put, yourself into the position where you have invested a large amount of time, effort and hope in order to achieve a far flung aim you will never know how success or failure will be.
Also never limit yourself to being an 'Airline Pilot', to be honest after years of 'alternative' professional flying I use Airline piloting as a casual backstop to pay the bills now I need a quieter life. It also suits that role perfectly.
One thing is certain though. Never let anyone who has no idea what they are talking about persuade you from trying. As, to be honest, to have tried and failed is always, always, always better than to have never had a go.