Hi Tom - Welcome to Pherotalk. 
If you want a straightforward demo of how pheros work, you could do a lot worse than try Ammo and Instant Shine - Individually and together. It won’t cost you a great deal, have a read of this thread and give us a little more info:
https://pheromonetalk.com/t/how-do-i-qualify-for-a-25-gift-certificate/19934
Ammo is a balanced mix of the three main pheros that produce a social/attractive and sexual package that is pretty straightforward to work with. Its androstenone content will also help to give you a healthy confidence boost. However, its not all down to the mones and you will need to work on your own self confidence and attractive behaviours apace - There is quite a bit of advice on that too in Mens if you want to search.
Instant Shine is another phero whose results are obvious - gives a happy/feelgood impression that again should be obvious to yourself and in anyone close by.
Used together, these two make a classic social/attractive mix that goes well in all sorts of social situation.
As you have a girlfriend, you may want to consider TUTH - Which is good for enhancing sex in an established relationship. It has a more overt none/sexual kick that will hopefully stimulate your GF, who is used to you but may not be so good socially in someone your age as it can come-off as agressive or overly horny as you are probably at the peak of natural none production yourself. None output decreases as we age.
Anyway, use wisely and don’t overuse - I hope you will see good results soon.
Another thread with all the basic info on doses, application etc: