There is no way to start some number of records from the end (or beginning).
But I assume you have some field that determines the order of the records. Assuming this field is indexed, you can start at a certain record by doing a query with >= some value and this will be fast since it can use the index.
If you need to select based on other fields as well, then you might need different indexes. For example, if you were doing “group = x and order >= value” then to make this fast you would need an index on group,order