Any single mom's who've done it all from start to finish? Looking for advice :)

Hey Mommit!

I'm currently a single mom. I have a delightful 9 year old boy (almost 10!) and am nearly 40. I've been a single mom for nearly eight years now and have a good relationship with my ex in that my son spends every other weekend with him. I am not dating nor do I truly have an interest in dating, BUT I am struggle with my stupid &^@&^4( biological clock!

I'm looking to see if there is anyone out there who has made the choice to have a baby while single. I would chose to use a sperm donor as I don't want to burden someone else with my desires. If you've done this, do you have any advice for me? Anything I should consider? Things I should be considering? Have any of you had a baby this close to 40? Or past 40? Is it worth waiting? I feel like I am really running out of time though I know that medically that may not be as true any more, but being a single mom it seems that younger may be better.

Thanks for any and all help!