I don't know the number of times that I've had parents contact me asking to please get them in my calendar because they had decided to do their own newborn pictures and realized quickly that the end result was not what they had hoped for. Some even purchased cameras comparable to the Canon that I use, spending several thousands on the equipment.
It's like getting your nails done... I mean, the nail technicians make it look sooo easy!! It's literally just brushing color, right? RIGHT!! It's a wonder I have a drawer full of nail polish, nail tools and several bottles still full of different types of acetone. But guess what? I still go to the salon to get my nails done, every two weeks! Why? Because I'm not an expert, in all my years, I still don't have the ability to fix my own nails so they look professionally done; even with all the expensive nail stuff I have.
The lesson here is... sure, you can attempt a DIY project. Purchase all the equipment that the professionals would use, watch all the YouTube videos instructing you how to do it... yet, you are faced with the results of an amateur. There is nothing wrong with that as long as in the end, you are content.
Capturing newborn portraits is a ONCE in a lifetime opportunity. I'd say, if you really want to have memories that are beautiful and will bring joy years from now, go ahead and invest in a professional photographer. Make sure you review their portfolio and you like their style. This is what will give you an indication of what to expect. Be sure to read their reviews and be certain they have a lot of experience.