This is not 100% accurate because not every month is exactly 4 weeks long but it is close and the easiest way to figure it out, so just take your weeks (26) and divide by four (because there are for the most part 4 weeks in a month) so that would put you at 6 months and 2 weeks or 6 1/2 months like FEOT said.
If you are 26 weeks now yeah that makes you 6 1/2. Just double checking myself lol