I get the feeling about being hesitant with the pressure, I'm also not a big drinker most of the time and I'm fairly introverted so I dislike having someone hovering trying to get me to make decisions. The first time I went a few years ago I was alone and very nervous, but after that first time it's easy.
Sometimes I think we give the impression it's going to be relentless and confrontational, but it really isn't 99% of the time. It's just them trying to keep you there buying (any) drinks and hopefully getting you to take someone off. The mamasans don't care what you drink as long as you're not sitting on empty forever, most of the time I'm just drinking soda and lime (Schweppes Manao Soda).
If the mamasan is asking you to pick a guy from stage and you either don't want to or haven't made a decision, just say "I will watch and chose later". Most of the time they get the hint and leave you alone for a bit while you decide to pick someone or pay your bill.
The MBs are usually the least pressure in the bars i've found, it's after the ST or LT they'll send messages and try to get you back. You can avoid it by just not giving them your Line or Social Media.
I still get a bit uncomfortable if the gogo is empty and I have a stage full of hopeful eyes looking at me, so maybe do a lap of the bars and look for one that isn't empty for the first time. If you go just before the show or during the show times it's more likely to have a crowd to sit and observe for a while.
I'm under 50 and not there atm to intro, but i wish you well.