The .40LA should be fine to learn on. If you find you want more power after a while, consider a ball-bearing motor like an OS .40 FX or TT Pro .40.
You don't need a power panel/battery/electric starter yet... Maybe never?
I haven't been flying that long, but OS engines start pretty easy after dialing in and all that extra stuff is alot to carry around.

Whatever you do or don't do... Get with an instructor!!! It could be the difference between learning to fly and ending up with a small pile of very expensive kindling.

See the AMA website to find a club near you.

Welcome to the sport!