+StrikeR+

If you are looking for something shorter, and if you haven't read it, perhaps Doki Doki Literature Club? One of the characters takes a pretty dominant role and if nothing else it is certainly an experience. 

I find the fact that most recommendations are nukige with femdom fetish very revealing  Oh well, it's clear that is not common at all. 
Let's see... I've just read Sharin no Kuni and if you pick Sachi's route she kinda takes the lead. Not that she's particularly mature though. 
In ef the second tale Yuuko can definitely be seen as deliberately approaching and trying to seduce Yuu. But again, not that she's the "mature type" and the situation is much more complex than all that... So... 
Ever17's Tsugumi's route might also be fitting. Actually, it might well be the closest to what you are looking for... The only problem is that the romance is fairly scarce. 
Anyway, I hope I gave you some ideas 

Idk. I find it pretty weird to classify someone as a person who takes the initiative like this. And this
Anway, wouldn't Asako fit the bill far better in this case?
Speaking of Grisaia, perhaps the OP can read the Grisaia:Phantom Trigger series. I think it fits into what he is looking for
 

I wouldn't say she's mature in that regard, but she definitely takes the lead when it comes to chasing Yuuji, as she constantly showers him with affection and cooks for him whenever possible.

Was she ever mature or did she ever take the lead from Yuuji at any point besides
 
Some of the above recommendations are Nukiges (Imouto Paradise, Starless) or have a lot of hardcore-ish 18+ scenes (Euphoria). Just thought I'll mention it in case you are just looking for a normal-ish VNs and doesn't like those genres

Amane from Grisaia (?)

Starless has dominant female leads, however calling them villains is probably more appropriate than calling them heroines. They also give of a mature vibe.

Welcome to Fuwa.

Welcome to Fuwanovel!  

Welcome, glad you're enjoying Tsujidou-san it's pretty darn good

hello and welcome.  hope you enjoy it here, and make lots of new friends.  

I hop so too as well, so let me say welcome to Fuwanovel and I hope you'll enjoy yourself here. Also if you need more VN Recommendations, just ask us here.

Werukamu tsu Fuwa!

Welcome aboard mate, hope you have a fantastic time here! Nice profile picture if I may add, purple hair is the greatest of colours, a- wait, what's that?

 

Hi all, decided to register here since this seems like a nice community for talking about visual novels. As for me i'm just the average person who enjoys visual novels, gaming and anime. As far as visual novels my favorites are:
 
The Majikoi series (my absolute favorite, a series very dear for me as it even helped me get out of depression sort to say a few times)
Muv-Luv series (i played this in a rough time as well, it was a very enticing and amazing story)
G-Senjou no Maou (with this one i had no personal problems when going in, but the main route really was amazing)
46+1 ChuSinGura (had its share of flaws, like misspellings and sometimes it cut rather weirdly but despite that they manage to keep the overall feel of the original which is why its one of my favorites)
 
As for now i'm enjoying myself with Tsujidou-san Jun'ai Road . 
 
With my brief description ending i will like to end on this note:
 
  Mina-san Yoroshiku Onegai Itashimasu!

Welcome to Fuwa! I hope our little community will meet your expectations. 

Hi there and welcome to Fuwa, have a nice stay here

well well, Welcome to Fuwa  こちらこそ よろしく いたします。
 

Welcome  and enjoy your stay.

Hi all, decided to register here since this seems like a nice community for talking about visual novels. As for me i'm just the average person who enjoys visual novels, gaming and anime. As far as visual novels my favorites are:
 
The Majikoi series (my absolute favorite, a series very dear for me as it even helped me get out of depression sort to say a few times)
Muv-Luv series (i played this in a rough time as well, it was a very enticing and amazing story)
G-Senjou no Maou (with this one i had no personal problems when going in, but the main route really was amazing)
46+1 ChuSinGura (had its share of flaws, like misspellings and sometimes it cut rather weirdly but despite that they manage to keep the overall feel of the original which is why its one of my favorites)
 
As for now i'm enjoying myself with Tsujidou-san Jun'ai Road . 
 
With my brief description ending i will like to end on this note:
 
  Mina-san Yoroshiku Onegai Itashimasu!

Hi all, decided to register here since this seems like a nice community for talking about visual novels. As for me i'm just the average person who enjoys visual novels, gaming and anime. As far as visual novels my favorites are:
 
The Majikoi series (my absolute favorite, a series very dear for me as it even helped me get out of depression sort to say a few times)
Muv-Luv series (i played this in a rough time as well, it was a very enticing and amazing story)
G-Senjou no Maou (with this one i had no personal problems when going in, but the main route really was amazing)
46+1 ChuSinGura (had its share of flaws, like misspellings and sometimes it cut rather weirdly but despite that they manage to keep the overall feel of the original which is why its one of my favorites)
 
As for now i'm enjoying myself with Tsujidou-san Jun'ai Road . 
 
With my brief description ending i will like to end on this note:
 
  Mina-san Yoroshiku Onegai Itashimasu!