I had two kids in 17 months. It impacted on socialising. One child had an ongoing health problem which wasnt sorted out until he was three and meant that I was forever cancelling at the last minute because he was ill. Yes I know my DH was just as capable of looking after him as I was but between the two of them we barely slept for years. To add to the other one has ASD and got up at 2am for 2 hours every night for nearly five years - we took turns to stay awake, we were derranged with tiredness. I am amazed we're all still alive!
Certain friends disappeared (my bridesmaid and childhood friend) but some stuck it out, kept calling, let me cry on them etc, didnt make me feel guilty when yet again I had to cancel a night out and I bloody love those friends and have, I hope, repaid their kindness when they have needed me since.
Friendships need work and you need to allow somebody to evolve whether thats because their career takes off, they have kids or decide to move to a yurt in Somerset (or all three). If you need someone to stay exactly the same then it wont work.