Hi
Using this application to enable my firewall on startup, adding it to my startup applications

http://gufw.org/

But I'd like to delay startup of this app for 2-3 minutes
Is there any way to do this?

Gufw is a frontend to ufw which is disabled by default. You can enable ufw using the command sudo ufw enable

Gufw does not need to be running for the firewall to be active. Why do you need a delay?

well if you want to delay it. Do not have it start up on boot, but have boot, or a file such as .xinitrc call a script that will start it instead, when user logs in, or just after system boots to a login screen, the first being a better choice, then within that script that is say for example, .xinitrc gets called at log in (depending on the system) then it calls the script that will put a wait state in the start of said script for 2 to 3 minutes before it starts the program.

sleep x Amount of time.
execute the program

if you do not use this methodology for this program, it will still work for other things needing the same thing. Because it is methodology that is being applied here. Not a programming language per se'