Start up PE Fund Musings

Whats up Monkeys 24 Y/O here living in UK. 1 Year IB experience at BB and 2 years experience working at a PE (One year long internship during undergrad and one post-IB). Got a return Grad offer from the PE I currently work at post-internship (it is a small fund).  The PE fund I work at is more of a private investment group. Used to be a small PE with two GP's and one LP (family office). The two GP's were Co-CEO's of the business that was sold to generate the family office. Essentially, rather than investing across asset classes as is the norm for FO, they opted for direct equity investments into LMM businesses. Made a few exits over the years, including some large ones and the two guys bought the family out of their stakes in the remaining portcos. A couple of years back , they invested into a group led by an entrepreneur and since then, it is essentially the three of them (two GP's and one entrepreneur) who have been making further acquisitions in similar industry sectors (Energy). The business has grown significantly since this time and now employs 6,000 staff and the 3 'Partners' are worth comfortably £500MM in personal stakes in these businesses. So you can see it is not really a PE but rather a private investment group making PE-style investments.  I was one of their first juniors and they really liked me and offered me a job. However, comp was very low compared to market and they have not given equity/carry to any of their other staff (including portco CEO's and the Groups overall CFO). This worried me so I decided to go into BB IB. When I joined banking, I was going from a company of 7 people to a massive institution and found the working dynamics very different and didn't enjoy moving from buyside to advisory. Said I would take a risk and a paycut to go back to the guys because I knew how fast the businesses were growing and how much responsibility and learnings I would get. The responsibility and learnings have been amazing and extraordinarily rare for someone my age. I am essentially number 3 in my organisation for origination and investment analysis for new deals so lots of responsibility. However, over the past year they have hired significantly and evolved into more of an acquisitive energy corp. rather than a PE style group. I really don't want to miss out on all the potential comp that being in PE would get me and am now essentially in a CorpDev M&A role , which is not really what I wanted.  Got offered a new gig elsewhere by former head of new investments (my old manager when I was an intern) who has recently become a GP at a new PE/Private credit start up firm. Offered me a much higher base (50%+), bonus of up to 100% and because of the risk associated since it is just starting out, I get participation in carry, which is almost unheard of for someone my age. Best thing is, since they raise deal-by-deal primarily (they have a great network of HNW and FO's) , I get carry cheques also on a deal-by-deal basis. Not a big fund by any stretch but the GP's are quite sophisticated so I am pretty confident that they'll be successful. I will be the first junior on the team with all other members being 15+ years older than me. I have a feeling I will get sweated but not too worried due to greater comp + exposure I will be getting.  I will be working mostly on the PE side but they said in lieu of them hiring out in the PC department, I will get to work across that too on a deal-by-deal basis and participate in carry there also. 

Seems like a no-brainer to join but also aware of the inherent start up risks associated and potentially my current bosses hating me forever. I would consider myself a loyal person and don't want to be switching around too much. Am I stupid not to take the new job? Am having second doubts.