I don't think sense is good for the original mytouch, because its old, and its gonna lag like hell, since it doesn't have enough RAM. Regardless, it is still possible, kinda risky though. If you don't have experience, it should take about 6 hours to complete everything.
This is the easiest thing I can tell you to do:
Follow these instructions to get CyanogenMod on your phone (Should take 5 hours and 30 minutes):
http://wiki.cyanogenmod.com/index.php?title=Full_Update_Guide_-_Fender/1.2
Then follow this to replace CyanogenMod with a Sense UI Rom (30 mins):
http://forum.xda-developers.com/showthread.php?t=695406
I personally prefer CyanogenMod over any Sense UI Rom, because of the many little features that I can't live without anymore. Such as call blocking, and vibration notifications when someone picks up your phone call.
If you have a friend thats a cellphone freak, you can ask him to do it for you, and blame him if something goes wrong.