Just like you changed your mind about travel plans midway through your vacation. You are allowed to change your mind and stay on the US and adjust. Generally, USCIS doesn’t care and they most likely won’t question you during the AOS process- unless they notice other red flags.
Be aware: your boyfriend has all the control and power if you adjust.
If he decides he no longer wants to marry, he wants to delay filing the adjustment packet, you have a fight and he decides to cancel the I130 you will be in trouble.
If you trust him and believe he will stand by you while you are unable to work, drive, or leave the country. Get married asap and file I130, I130a, I485, I131 (we suggest filing this in case you need to return home for an emergency- but that might not happen if your family is already in the US) , I765- if you want to work and get a SSN so you can open a bank account and start gathering evidence of a real relationship.
Remember you don’t have to wait to file this paperwork. Good luck! And I hope your case is approved quickly and you are not stuck waiting in the US unable to work or travel for 12+ months.