at what age does the second "puberty" [masculinisation] of the body happen? i heard its somewere in the twenty's but i want to make sure i got some time left before this happens and the reason for it is that

in a few days i will be 21 years old and you can say that my body did not masculine to its full potential and im rather slim short and my shoulders arent too broad to a point me and my friends do believe that if i transition in this state i would have a realy good chance of passing without too much problem's
what is the issue? im currently volunteering and i got 10 months left untill im finishing my volunteering. this volunteering grants me a lot of privileges and money for later on in life [kind of saving's] but im afraid that this second masculining would happen within those 10 months and my body will change into something more "manly" and if it will i would better make some decisions and quick but before i do that i want to know how long do i have [on avarage?] untill this happens

lots of thanks for anyone with info

Well usually people say the "second puberty" starts with the thirties, or mid-thirties.
But the hormonal changes are more or less slow but constant, they're just getting really noticeable at that age.
Depending on the amount of T and DHT you have 'masculinisation' will become visible earlier or later. That's always a bit different for every person.

Look around you. There are 24 year old people that still look like they're 16 and there are people around the same age that look a lot older.

But if you really want to start HRT you shouldn't worry to much. A lot of people here reported that after some time on estrogen they start to look a lot younger to other people than they actually are.
Also if you have currently (with nearly 21) have very slim shoulders i don't expect any big change there. Most of your skeletal growth is already done and changes will mostly happen throguh increases or decreases of muscle mass.

well im not so sure how you measure shoulder broadness but it does seem like its not so "developed"

but thanks for the answer

Well let's give you an example then. ^.^

I'm currently 24 years old and 6'3'' tall.
And i still have my very "underdeveloped" shoulders of 18.110in. They didn't change for the last 4 years.
And i know cis women that have 18.898in shoulders with a height of only 5'5''.

Your experience can of course differ from mine, but in the end only the overall proportions matter.
And there are a lot of different and common body shapes in regards to women ( http://www.joyofclothes.com/style-advice/shape-guides/body-shapes-overview.php ).

ok thanks