I went by the same chart above.. I would say your 6months ;)
First trimester:
Month 1 week 1-4
Month 2 week 5-8
Month 3 week 9-13
Second Trimester:
Month 4 week 14-17
Month 5 week 18-21
Month 6 week 22-26
Third Trimester:
Month 7 week 27-30
Month 8 week 31-35
Month 9 week 36-40
Congratulations you just started your 6th month :)
5 1/2 months. (4 weeks = 1 month)
i believe is the starting of your 6th month