Boring Short Hair

A: Short hair isn't boring any more than long hair is. The truth is, a hairstyle isn't defined by its length. It's defined by its cut, texture, and how you wear it. A poorly styled long hairstyle can look just as boring as a neglected pixie. On the other hand, a well-cut short hairstyle can be elegant, sophisticated, edgy, or glamorous.
Trust Your Hairstylist’s Advice
If your hairstylist believes a pixie cut will flatter your face shape and hair type, I'd be much more inclined to trust that advice than your sister's opinion. Hairdressers spend years learning which styles complement different people. Your sister simply has her own personal preference, and there's nothing wrong with that. But her taste doesn't have to become yours.One of the biggest advantages of short hair is that every detail of the haircut stands out. Layers, texture, bangs, and shape become much more noticeable, giving you plenty of opportunities to create different looks. The same haircut can look completely different depending on how you style it.
The key is choosing a cut that works with your hair instead of fighting against it.
Pixie Tips for Fine, Straight Hair

A pixie with longer layers on top or an extended fringe is an excellent choice. The added length creates movement and gives you several styling options. A lightweight texturizing paste or matte styling cream can add volume, lift, and definition, making fine hair appear much fuller.
Pixie Tips for Thick or Wavy Hair

Instead of trying to tame every wave, let your hair's texture become part of the style. A layered pixie removes bulk while allowing the waves to create softness and movement. Finish with a small amount of styling putty or cream for separation and definition without stiffness.
Pixie Tips for Curly Hair

Short curly hair can be absolutely stunning. Many curly pixie cuts feature closely cropped sides with more length on top, allowing the curls to become the star of the hairstyle. A curl cream or lightweight gel will keep the curls defined, smooth, and frizz-free while maintaining their natural bounce.
Don’t Let Fear of Change Stop You
Don't let fear of change stop you from trying a hairstyle you've genuinely been excited about. You were ready to get a pixie cut before your sister made her comment. That suggests the hesitation isn't coming from you. It's coming from someone else's opinion.Hair grows back. If you try a pixie and decide it's not for you, you can always grow it out. However, keep in mind that growing out a pixie cut to shoulder length takes about two years, and reaching mid-back length can take up to four. But if you never try it because of one person's criticism, you'll probably keep wondering what might have been.
From what you've shared, I'd encourage you to go ahead and make the appointment. If your hairstylist is confident that a pixie will suit you, and it's the haircut you've been wanting, don't let your long hair hold you back. Weigh the pros and cons, take a deep breath, and make your decision! The final choice is yours.

Emotional Rollercoaster
Going directly from long hair to a pixie cut in a single appointment is a drastic transformation and it helps to be mentally prepared for the emotional side of makeover.Cutting off significant length can feel very liberating, fun, and thrilling. However, it can also bring a sudden wave of emotion. Long hair often acts as a security blanket, so seeing a completely new you can trigger instant regret, even if the haircut looks fantastic. Don't panic if your first thought in the chair isn't pure joy. Give your brain a few days to adjust to the change.
©Hairfinder.com
See also:
Tips and ideas for short hair
Is short hair professional?
How to make short hair more feminine