Can I board my train from booking point which is one station before my boarding point?

From IRCTC site:

If found travelling without any proper authority to travel, passenger will have to pay fare with penalty between original boarding point to changed boarding point. Boarding station can be changed before 24 hours of the scheduled departure of train.Boarding point change is not allowed for current booking ticket

From Make My Trip:

While you may choose a boarding point as any station on the route of the train, you would have to pay the fare as applicable for Reservation From – Reservation To stations. For example, if you are booking a ticket from Mumbai Central to New Delhi and choose the boarding point as Kota Jn, then you can board the train only at Kota Jn and not between Mumbai Central and Kota Jn. You would however have to pay the fare for Mumbai Central to New Delhi

Before you board at B, if the TTE comes for his rounds, and he sees that your seat is empty, if he wishes, he may wait till the next point before allotting your seat to a waitlist or RAC person. He has all rights to do this or he could fine you.

From IRCTC again regarding change of boarding points

The boarding point change is available , Only for the train tickets that booked online not for the reservation counter tickets. But the online tickets can be changed through 'Electronic Reservation Slip' before 24 hours scheduled departure of train as per extant Railway rules in reservation counters.

You could instead book from A to C and until 24 hours before the departure of the train you can change your boarding point to B with no issues at all. I think you're booking from A to C due to better availability of seats quota from A than from B. If this is the case, its always better to book ticket from A to C and then change A to B. That way you don't have to pay the fine for not travelling between A to B as per rules

As I understand your question: the train runs from A, to B, and thence to C. You are at A, and buy a ticket. A is therefore your "booking point."

The ticket you purchased is good for passage from your "boarding point" (B) to your destination (C). The ticket from B to C entitles you to be carried by the train from B to C. It does not give you passage from A to B.

Said in other words: a ticket from boarding point to destination does not necessarily include passage from the booking point to the boarding point. If you wanted to ride from the booking point (A) to the destination (C), you would buy a ticket between those two points; because A-to-C is a longer distance than B-to-C, the A-to-C ticket will be more expensive.

Your first sentence is "If i am boarding from my booking point which is one station before my boarding point, will I be considered as without tiket between booking and boarding point." Assuming this is a question, the answer is "Yes, you will be considered as being without a ticket between the booking point and the boarding point."