one month prego... new job january

Hey guys.. so we found out we are 1 month pregnant.. yay.. but here's the thing my work shut down beginning of December so I found a new job I start the second week of January.. (were not talking a entry level either.. it's a high-end position that I worked so hard from college and management experience I scored this amazing position).. I am on a 3 mnths probation.. this is my 2nd child an I'm already showing... at one month. I'm never going to be able to hide it until I'm 4 months prego which would be the time my probation is up.. plus I have to wear there dress shirts..so hard to hide.. so what do I do. it seems like a great company.. do I hide it for as long as possible an then tell them an be honest.. you know I appreciate this job I will give it my all blah blah.. or do I go in my 2nd day and tell them this is what's up if they want to let me go fine.. if not then great I will work my ass of for them right up to August my due date.. and even take on files if they need while I'm on maternity?? I feel honesty is so important. their impression of me matters but I also don't want to loose the job but here's the thing if they let me go now I can find another job still without fully showing.. or I chance it and wait it out as long as possible?