Should I get a lawyer ??

You should at a minimum invest in a consultation with an experienced immigration attorney. Since you entered on a B1/B2, there are issues, right there. Did you enter with immigration intent? How soon after your entry are you marrying? Did you communicate about marrying prior to your entry? How long have you been in the U.S. since your entry? Since you could have entered the U.S. (or can still return to your home country prior to marrying... ) and have your fiance' complete a Fiance Visa (typically 1-3 months), enter, and marry in 90 days, and file for adjustment, this way no you are allowed to have immigrant intent and enter to marry...
so there are different ways to proceed, different time variables, and evidentiary requirements. As far as if you might have any other issues as far as inadmissibility preventing you from adjusting status in the US if you submit the 1-130 and I-485 - if you might need a waiver - if you have a BAR you would be facing - if the affidavit of support is met or if a joint sponsor is needed... Definitely.