Now my age is 18. At the age of 33/34, can I become a complete a neurosurgeon or not?
If you take the MCAT next year, when you are 19, and have acceptable prerequisites, which typically include a college degree, which you will either Doogie Howser yourself into medical school immediately, or you will require an additional 1-2 years to achieve an undergraduate degree. Then you will matriculate into medical school at 21.
21 + 4 is 25.
At 25 you will finish medical school at the very top of your class, with an excellent step 1 score or COMLEX if we want to be equal opportunity. You will then start your PGY-1 year at Johns Hopkins, again at the age of 25. Neurosurgery residency is 7 years.
25 + 7 is 32.
You will finish your neurosurgery residency (which has it's own forum on this site by the way, so feel free to explore over there given that they know much more about this than we do) at the still tender age of 32. You will then join a private practice spine group in Sacramento, CA, where you will perform ACDFs on the 40-70 private insurance crowd for an additional 30 years.
32+30 is 62.
You will retire at the age of 62 as a full partner in your group, and split time between your golf-course adjacent house in Sacramento and a condo in Santa Fe, where you will spend the winter holidays with your family, which by then will include 2 children and 4 grandchildren. You will drive a Mercedes 600SL from your 40th birthday until you turn 60, updating the model every 4 years. At 60 you will transition to the S-class, because it will be more befitting your age and stature. You will wear exclusively Rolex watches, the first of which you will purchase with your signing bonus, which of course will be acquired at the age of 32.
In summary, 19+1+1+4+7=32. At the age of 32 you "can become a complete a neurosurgeon" as you asked. As stated, you will retire at 62.
Please let me know if we can provide you with any additional information. We are all super eager to help, here on the neurology forum. Again, I would also kindly refer you to the neurosurgery forum, which might be a more pertinent place to ask questions about becoming a neurosurgeon.