I want to become Muslim, but I doubt all 6 pillars of Faith. If I don't pay attention to these doubts can I say my Shahada and become Muslim?
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If the doubts that come to your mind are mere whispers as it appears, then just ignore them and not pay any attention to them and hasten to embrace the true religion of Allah Almighty.
Your embracing Islam in this case will be valid and these whispers and thoughts will not affect you.
Our advice to you in any case is to take the initiative to embrace Islam, for there is no salvation in the Hereafter except for the one who meets Allah as a Muslim.
Then if you have any issues or questions, you may ask them to trustworthy scholars and be confident that you will get convincing answers, Allah willing.
You must be firmly certain of the Oneness of Allah Almighty and the truthfulness of His Messenger for the evidence for that is clearer than the sun, praise be to Allah.
For more benefit on the evidence that Islam is the true religion, please refer to Fatawa 86091, 102075, 16595, 88906, 88051, 173389, 85234, 81979 and 9263.
For more benefit that everything in the universe testifies that Islam is the true religion, please refer to Fatwa 111063.
Allah knows best.
You can search for fatwa through many choices