It's a good idea. You may want to plan a second activity like lunch or a walk in the park as well.
And just be direct. Something like "Hey, do you want to go on a date with me? We can grab something to eat and go to the comic store."
If she says no, don't push it. Just say okay and wish them well.
I too was terrible at talking to girls. I still am but my girlfriend doesn't seem to mind lol
Whatever you do, just don't try any pickup artist or smooth talking tactics. It's gross and cringey, doubly so if you don't have the confidence to pull it off.
I would also disagree with a lot of the other comments, if you want to date this person, make it clear you want a date. Don't try to do the be friends then turn it romantic thing. It can work but not when you already know you want to date them.