Math Major Hesitant About IB

Hi,

For some background, I'm a senior math major in college in my last semester at a semi-target. I spent last summer at a lower-tier bb in NYC and accepted a return. Anyway, I am posting because I'm looking for some advice or some affirmation because I'm feeling regretful over choosing to start in IB. The reason I'm feeling some regret is because I feel that a trading role or quant trading role might suit me better, but I found IB my Sophomore year when I didn't know about anything else and have been focused on recruiting from then until I got my offer, so I never studied for or applied to more quantitative roles. 

I'm scared that starting in IB will shut the door for me to ever get into anything more technical if I end up hating it. Now that I know that the pay is quite good in many of these quant type roles in addition to having much better wlb, in addition to experiencing the long hours of IB during my summer and the nature of the work, this really scares me. The one thing that does keep me hopeful is that the work that the full time analysts were doing seemed more interesting than what they were giving us interns (market was slow so I was on some database projects, updating slides, etc.). After the summer, staying in IB or going to PE doesn't seem like something I'd like to do. I can see myself enjoying a venture capital role or working for a startup, but I'm aware that VC is difficult to break into even with an IB background, and I'll probably have to take a pay cut even if I do manage to break in. I could also see myself at a more technical trading desk within s&t. 

I am scared of ending up in a career where I don't feel intellectually stimulated, and am working very long hours. I would like to be in a role where I have time to have side projects - whether it be starting a business or investing in rental properties or building software, this seems to be impossible while in IB or most PE seats. I knew that the hours would be long going in, but I didn't really think of all the opportunity cost that entails since there's no time for side projects, and I also thought PE would be better which I am now learning is not necessarily the case. 

Anyway, my options are as follows: 

Do nothing now, start in IB and recruit for VC/PE/HF (not sure if I should choose one or recruit for everything)

Start grinding interview prep for trading roles and try to get something last minute, then renege (my internship experience is exclusively in finance so I think my chances aren't great.)

Apply to MFE or masters in math programs and try to go into quant/quant trading from there

Do an extra semester of undergrad to take relevant courses for quant trading (stochastic calc, stats, econometrics (?),etc) and recruit then.

Do IB and if I decide it's not right for me, then go get MFE/masters and change careers (is this even possible?)

Lastly, I know that I'm in a good position, going into a lucrative industry at a big bank, and want to be realistic. I am also aware that I'm experiencing the grass is always greener syndrome, since I wanted nothing more than to be in the position I am right now just a few months ago. Common sense tells me I should just go with it, especially since I'm in my last semester, but I just can't shake the thought that I will be bored and regret going into IB or finance generally. 

Would appreciate any advice, especially from math majors, since you all know the feeling of going from an highly intellectually demanding field to IB and I'd like to hear whether you feel stimulated in your role or if you regret not going into something more technical. Thanks guys.