who do i choose?

so i have been talking to two guys at the same time because i didn't think it would be something serious. a few days ago i went out with one guy and we had a lot of fun. it was really a great time. today i went out with the other guy and also had great time, we talked alot and honestly really clicked together. i know it's early to tell what will happen cuz i only went out one time with each of them, but i don't know what to do if it gets serious with one of them, also i really don't know which guy to choose to be more serious with cuz they're both really great. i don't want it to be like I'm leading one of them on. i would really want to be clear before it gets serious with both of them, don't really want to be an ass if it does.

does anyone have some advice for me?