I think my computer is to slow for this game or something.

I bought Rust last night and I finished the download and everything, I tried to play it but it wont let me join a server at all, it loads to the Character loading and it like takes me back to the main menu every time I try to join a server… My little brother tried to play it a few minutes ago, he got into a server but it was way to laggy. I’ve changed the graphics to a lower setting but it didn’t help at all. Is my computer just to slow for this? I have a Toshiba Windows 7 with intel pentium I’m not sure if thats one of the recommended for the game but I had to try it.