Ah so if my route when I go to Isesaki is fr Minami-senju to shin isesaki; when I go back home it will be the same route?Yes. However from what I can see from Google Maps there isnt really an alternative route. What I wanted to warn you about, is that e.g. if on the way home for any reason you want to go e.g. through Omiya (because you want to visit a friend there), that is not possible with the commuter pass. You need to stay on the "track" that you have the commuter pass for.
Also I think that some of the very fast trains might be excluded from commuter pass.
If you are currently in Tokyo, really the best you can do is ask to a Tobu rail counter and let them explain to you which options there are and if any of their express trains are excluded.
Should I be worried about the time?Well, it is a 2 h commute in 1 way to get from Minami Senju to Shin Isesaki plus you will need to add some more commuting time from Shin Isesaki to your driving school. So roughly you will spend every day you go to driving lessons about 5 - 5.5 h on transport or waiting for transport. I would be worried about so much time spent. Are you not working or attending university?
Also it is about 5,000 yen both ways to even get there and a commuting pass, as explained above, will only be cheaper (and not by drastic amounts) if you go there at least 5 days a week. So very roughly I would expect that the commuting pass will be about 80,000 yen per month. (Just an educated guess,I tried finding the actual amount, but can't find a calculator on the Tobu webpage... but it does lists their offices and hours:
https://www.tobu.co.jp/railway/ticket/commuter_pass/I would probably recommend to go to Kita Senju and ask there. That was a place where a lot of foreign tourists would start their trip to Nikko, so some of the employees might be able to speak English.
Are there really no other options closer to Minami Senju that offer English driving lessons? Maybe the friend who recommended the school in Gunma was living in Saitama or otherwise closer to that school so it made sense for her/him. But living in Tokyo it seems a very time intensive option to go to Gunma for each driving lesson plus with the commute it will likely also be more expensive than a school in Tokyo or let's say Chiba.
Did you have a look if there are somewhere intensive driving lessons? (gasshuku menkyo (合宿免許) These are like summer intensive courses, let's say 2 - 3 weeks somewhere in the countryside to learn driving and come back home with the driving license. I.e. you actually stay there.
Your decision will also depend on if you actually already can drive or not. I.e. if you need to learn driving from 0 you will obviously need a lot more driving lessons. However if you actually have a driving permit from your home country, but need to pass the Japanese driving exam because you cannot simply switch it to a Japanese one, well, you already know how to drive, so you will need much less driving lessons.