One thing that the SE pagination component has over yours is that it displays how many pages there are total.
This is something to consider, will the user get frustrated if he presses your "Last-link" and expects maybe page 15 but ends up on page 115?
Another UI feedback that your version lacks is indication of further pagination. At first I thought "9" was the last page in your pagination. It was actually from seeing that the first number in the pagination was "5" that I understood that there might be additional pages after 9, but the UI doesn't clearly communicate that. The use of "..." that SE utilizes is one intuitive way of communicating this.