Yep it's fine, I had the same issue till I recently bought a SHH shifter.
Also, auto-clutch does not preclude the use of the clutch pedal! So if you have a clutch pedal, you can start practicing your clutch skills even before you buy a shifter (if you do buy one, that is). I'm saying this because usually, in single player, if you use auto-clutch, you also end up using auto rev matching (unless you tick off that option). SRS does not let you automate rev matching though (except if the car does that itself), so you might as well do heel and toe shifting even with the paddles. Or at least just make sure to give a small nudge to the throttle while downshifting, just like you would if you were using a H-shifter - otherwise you might lose traction.
Anyway, my times improved quite a lot using a h-shifter after a quick adaptation period, I was really surprised. So it's not like you're getting an unfair advantage using paddles, especially in cars that in reality use h-shifters.
Also, auto-clutch does not preclude the use of the clutch pedal! So if you have a clutch pedal, you can start practicing your clutch skills even before you buy a shifter (if you do buy one, that is). I'm saying this because usually, in single player, if you use auto-clutch, you also end up using auto rev matching (unless you tick off that option). SRS does not let you automate rev matching though (except if the car does that itself), so you might as well do heel and toe shifting even with the paddles. Or at least just make sure to give a small nudge to the throttle while downshifting, just like you would if you were using a H-shifter - otherwise you might lose traction.
Anyway, my times improved quite a lot using a h-shifter after a quick adaptation period, I was really surprised. So it's not like you're getting an unfair advantage using paddles, especially in cars that in reality use h-shifters.