So I just started my home bakery about a month ago and have done a few orders here and there. This weekend though I'm doing a baby shower cake * two tier* and decorated cookies for about 35 people. I live in a pretty small town where everybody knows everyone... I advertise in the bigger city that's near me, so I feel like I don't have issues giving people prices.

Buuuut, this baby shower job is for people that are friends of my parents. I normally charge like $3 dollars a serving, but I rounded down a bit because of the cookies. So all in all her pricing is only 120, a pretty fair price.
I told my parents and they immediately looked like a asked for the lady's newborn as payment. They were actually a little upset that I charged so much and that they would never pay that. My stepmom and dad got married a few years ago and "only paid 300 for a cake that fed 200," so they don't understand my pricing.

I've read on here a lot that you charge what you're worth and I think I'm pretty decent. I worked professionally before scouting out on my own. It's just that this hiccup is a little discouraging, I feel like my business is going to just flounder. I just emailed her about the prices and she hasn't gotten back to me, but I'm just so desperate for this business to work.
Any advice on confidence?

Wow. To be honest I'm a bit shocked your parents don't support you! Doesn't matter who the order is for, you should stick to your guns and charge what your work is worth. Otherwise you will have people lining up for "discounts" because they are friends of you, your siblings, parents, auntie, grandparents. ..etc etc...

I have a very small circle of people I don't charge. Strikt rule is "keep your mouth shout about that fact" lol.

I mean good for them they paid so little for their wedding cake. But they can't expect you to make a living if you can't earn decent money with what you are doing!

One:  Your parents are not your customers.  People who are willing to pay premium pricing for custom cakes are your customers.

Two:  Friends of your parents may not be your customers either. 

Three: Friends/family may think they are doing you a "favor" by offering to purchase a custom cake.  There will be a learning curve for them and a teaching curve for you to get rid of those notions.

@Apti  said it best!! I don't bake for my family I don't even offer up anything except our practice leftovers why bc they are not my target market. We were asked to do things for my husbands side of the family and we said we were too busy to take anymore orders why because we aren't marketing to them and there is a level of expectation among some family members/friends that we aren't willing to deal with. We don't have a friend or family discount. I do cookies for my neighbor and her sister often and I do them for a lesser price bc I do a simple iced cookie not my normal hand piped ones bc they ship them (to family) and don't want all my hard worked ruined in shipping. But that price is for them only and I don't offer that to anyone else. And when they want cookies hand piped they pay the full price. So they order both often. Maybe I'm just fortunate to have good customers from the start. There are people out there willing to pay what your work is worth. My husband always says don't be afraid to charge what we're worth they'll either say yes or no and either way it's ok. Do you have a basic price list in place? If not I highly recommend having one and referring people to it weeds out some of the awkwardness if your prices don't fit in their budget. I basically say this is the price per item tiered cakes are consider custom, the price reflects that and each tiered cake will be priced according to the specifics of that order. 

ever since I put clear pricing and terms on custom orders people who email or call know what they want and know it will cost more  before I was dealing with people not having a clue about how much things would cost  even though I had a menu it wasn't clear enough. I'd make some price list and hand them out to potential customers as well as family and friends and  stick to your prices!!! 

Also one big thing I learned is to ask when taking orders or quotes is ask if they have a specific price point or budget. Then you know what your peramrters are and whether it's even worth the time quoting them. That also eliminates the nail biting wait to see what they'll say about your price you put something together in their price range they can't argue with you on their budget. Starting out is hard and it doesn't help when people especially family balk at your prices but understand that there are people out there who appreciate what we do you just have to find them :) 

You have to set your prices based on your expenses, what your hourly wage is and what your profits should be. Other people have no idea what those things are, so don't bother asking them for advice. 

And family is the worst. My husband stays totally out of my business unless I specifically ask him his opinion on something. I don't give him advice on how to do his job, and he knows better than to try to tell me how to do mine! If you set your pricing correctly you should have no reason to ask anyone's feedback on it, especially someone who has no knowledge of your business situation.

Is the $120 just for the cake or the cookies AND the cake?

120 just for the cake. I charged her 30 for the cookies.

It's still a really good deal for them, but if your cookies are decorated you are way undercharging.  If they don't go for it don't feel bad, they are not your customers.