Force a fork - is that possible?
It is absolutely possible - but not necessarily feasible - for an attack to branch off in the past, and create a new majority chain from that.

However, it effectively means that you or the miners who are participating in this attack need to mine faster than the rest of the network combined. Otherwise, you'll never be able to 'outrun' them, and the further back you start, the less likely it is you'll ever catch up.

For this reason, this is also called a 51% attack. For anything further back than a few blocks, you almost certainly need a majority of the hashrate to succeed.