Congratulations!
I don't know of any support groups, but mumsnet is a kind of support group. I certainly found it very useful for bits of advice and support when dd was young, and still.
I can't think that support or advice you need will be much different from the support any first time parents need.
I think possibly as an older first time mum (I was 38)I was more set in my ways so it may have been more of a shock to the system and more of a change. But I have no way of really knowing that.
It can be physically quite demanding at times and I suppose you cope with that aspect better with a younger body.
However, there are advantages as well. I'm calmer, I'm more sure of myself, I have more resources, and my lifestyle is more sedate.
Having been a bit ambivalent about having children, my dd arrived and for a while I thought 'wtf have I done?' and that I wouldn't cope. But now (she is a toddler) I can honestly say that she is the most amazing and wonderful addition to my life and I'm so glad that I have her, I can't really put it into words.
I'm just trying to say that it will be hard at first, but very much worth it. Good luck.