While not having much experiance with the 2 drugs either, I cant really give you my opinion. But i have been looking up info about which to take first also. (from info that i have gatherd) acid has more intense visuals (if you take more than one hit), and is easyer to control. Shrooms have some pretty intence visuals, but they seem more fake. it is more likely to bad trip on shrooms.
Personally, I would try either one first and im going to be trying acid very soon. just remember to have a sober sitter (for your first time atleast) and to take a little for the first time, or it will make you never wanna do it again.
O and welcome to GC, ya that was my response when i first tried weed, just make sure to not get into anything addictive!