I'm at level 10 right and want to do Lonesome Road but the game suggests that I be 25 or higher?? Is this really necessary??

Play it and have fun. I did it at level one and couldn't get very far.

Depends on what difficulty you are playing and what gear you have... you can always back out of that dlc if its too much

On normal yeah. Sometimes I go there at alow level. You can find good weapons if you know where to look. Don't be ashamed if you have to run through rather than fight