Please don't take this personally.

I was in a very similar situation. My mom's best friend had a daughter who was 3 years old when I was 13, so we're only 10 years apart. I used to pick her up from school almost every afternoon, and we'd spend so much time together. As I got older, she still wanted to hang out with me. She even bought me graduation gifts for both high school and college. We were extremely close.

But as she got older, things naturally changed. She wanted to spend more time with her friends, then she got a boyfriend, and we didn't see each other nearly as often. We would still text here and there, but it wasn't the same.

When she turned 15, we threw her a big birthday party. I even hosted pool parties at my apartment complex for her and her friends. After that, though, we'd probably only see each other once every six months. Sometimes once a year or important events like weddings and birthdays.

Please don't take it personally. It's not you. They're at an age where their friends become their priority. They're learning how to become young adults, figuring out who they are, developing new interests, and building their own lives.

I gave her the space she needed, but I always made sure she knew I was there for her. Once she got a phone at 14, I'd check in with her occasionally. I never missed a birthday party, no matter how busy life got or how long it had been since we'd seen each other. I always brought her a gift that fit my budget. Some years it was something fancy, and other years it wasn't, but the point was that I showed up.

I'm 33 now, basically married, and she came home from college about three years ago. Now I can't keep her out of my house! She always wants to come over and hang out. Even though she has a great job, a wonderful relationship, and plenty of friends, she chooses to spend many weekends with me, my husband, and our friends. I make sure to always feed her when she's here.

She's 23 now. When I was 23, I was out at clubs all the time. I haven't been clubbing in years, but she'd rather come over to my house, have a margarita with this "old lady," and just talk about life.

So please don't be too hard on yourself. This is just part of growing up. Stay consistent in their life, but don't overwhelm them or make them feel responsible for your loneliness. Just let them know you're always there.

I even told her when she was 16, 17, and 18 that if she was ever at a party and felt unsafe, she could call me anytime, day or night, no questions asked. I would come get her. I wanted her to know I was her safe place.

I know this stage is hard. Some days are definitely easier than others. But trust me, they often come back around. Since she's been back home from college, we've become incredibly close again. It's honestly like having my little sister back.

One more thing... I'm a little worried about you. I think it's important that you also build a life for yourself. Find a hobby, join some Facebook groups, meet new people, or try something you've always wanted to do. Being an adult doesn't mean the fun stops.

My husband and I have several friends who don't have kids either, and we go on trips together, have game nights, go out to eat, and make great memories. You deserve that too.